diff --git a/pandas/core/arrays/sparse.py b/pandas/core/arrays/sparse.py
index 08c961935a9902..a63b3fb53625f1 100644
--- a/pandas/core/arrays/sparse.py
+++ b/pandas/core/arrays/sparse.py
@@ -10,35 +10,35 @@
 
 import numpy as np
 
-import pandas._libs.sparse as splib
-import pandas.core.algorithms as algos
-import pandas.core.common as com
-import pandas.io.formats.printing as printing
-from pandas import compat
 from pandas._libs import index as libindex, lib
+import pandas._libs.sparse as splib
 from pandas._libs.sparse import BlockIndex, IntIndex
 from pandas._libs.tslibs import NaT
+import pandas.compat as compat
 from pandas.compat.numpy import function as nv
-from pandas.core.accessor import PandasDelegate, delegate_names
-from pandas.core.arrays import ExtensionArray, ExtensionOpsMixin
-from pandas.core.base import PandasObject
+from pandas.errors import PerformanceWarning
+
 from pandas.core.dtypes.base import ExtensionDtype
 from pandas.core.dtypes.cast import (
     astype_nansafe, construct_1d_arraylike_from_scalar, find_common_type,
-    infer_dtype_from_scalar, maybe_convert_platform
-)
+    infer_dtype_from_scalar, maybe_convert_platform)
 from pandas.core.dtypes.common import (
     is_array_like, is_bool_dtype, is_datetime64_any_dtype, is_dtype_equal,
     is_integer, is_list_like, is_object_dtype, is_scalar, is_string_dtype,
-    pandas_dtype
-)
+    pandas_dtype)
 from pandas.core.dtypes.dtypes import register_extension_dtype
 from pandas.core.dtypes.generic import (
-    ABCIndexClass, ABCSeries, ABCSparseSeries
-)
+    ABCIndexClass, ABCSeries, ABCSparseSeries)
 from pandas.core.dtypes.missing import isna, na_value_for_dtype, notna
+
+from pandas.core.accessor import PandasDelegate, delegate_names
+import pandas.core.algorithms as algos
+from pandas.core.arrays import ExtensionArray, ExtensionOpsMixin
+from pandas.core.base import PandasObject
+import pandas.core.common as com
 from pandas.core.missing import interpolate_2d
-from pandas.errors import PerformanceWarning
+
+import pandas.io.formats.printing as printing
 
 
 # ----------------------------------------------------------------------------
diff --git a/pandas/core/groupby/base.py b/pandas/core/groupby/base.py
index 9ef30b8fd021f7..1bf97690a84ed7 100644
--- a/pandas/core/groupby/base.py
+++ b/pandas/core/groupby/base.py
@@ -6,9 +6,10 @@
 
 import types
 
-from pandas.core.dtypes.common import is_list_like, is_scalar
 from pandas.util._decorators import make_signature
 
+from pandas.core.dtypes.common import is_list_like, is_scalar
+
 
 class GroupByMixin(object):
     """ provide the groupby facilities to the mixed object """
diff --git a/pandas/core/groupby/categorical.py b/pandas/core/groupby/categorical.py
index 3e653704bbace5..85f51323a97b53 100644
--- a/pandas/core/groupby/categorical.py
+++ b/pandas/core/groupby/categorical.py
@@ -2,8 +2,7 @@
 
 from pandas.core.algorithms import unique1d
 from pandas.core.arrays.categorical import (
-    Categorical, CategoricalDtype, _recode_for_categories
-)
+    Categorical, CategoricalDtype, _recode_for_categories)
 
 
 def recode_for_groupby(c, sort, observed):
diff --git a/pandas/core/groupby/generic.py b/pandas/core/groupby/generic.py
index a832eecf87721c..3ed80d266ce4df 100644
--- a/pandas/core/groupby/generic.py
+++ b/pandas/core/groupby/generic.py
@@ -8,39 +8,40 @@
 
 import collections
 import copy
-import warnings
 from functools import partial
 from textwrap import dedent
+import warnings
 
 import numpy as np
 
-import pandas.core.algorithms as algorithms
-import pandas.core.common as com
-import pandas.core.indexes.base as ibase
-from pandas import compat
 from pandas._libs import Timestamp, lib
+import pandas.compat as compat
 from pandas.compat import lzip, map
 from pandas.compat.numpy import _np_version_under1p13
-from pandas.core.arrays import Categorical
-from pandas.core.base import DataError, SpecificationError
+from pandas.util._decorators import Appender, Substitution
+
 from pandas.core.dtypes.cast import maybe_downcast_to_dtype
 from pandas.core.dtypes.common import (
     ensure_int64, ensure_platform_int, is_bool, is_datetimelike,
-    is_integer_dtype, is_interval_dtype, is_numeric_dtype, is_scalar
-)
+    is_integer_dtype, is_interval_dtype, is_numeric_dtype, is_scalar)
 from pandas.core.dtypes.missing import isna, notna
+
+import pandas.core.algorithms as algorithms
+from pandas.core.arrays import Categorical
+from pandas.core.base import DataError, SpecificationError
+import pandas.core.common as com
 from pandas.core.frame import DataFrame
 from pandas.core.generic import NDFrame, _shared_docs
 from pandas.core.groupby import base
 from pandas.core.groupby.groupby import (
-    GroupBy, _apply_docs, _transform_template
-)
+    GroupBy, _apply_docs, _transform_template)
 from pandas.core.index import CategoricalIndex, Index, MultiIndex
+import pandas.core.indexes.base as ibase
 from pandas.core.internals import BlockManager, make_block
 from pandas.core.panel import Panel
 from pandas.core.series import Series
+
 from pandas.plotting._core import boxplot_frame_groupby
-from pandas.util._decorators import Appender, Substitution
 
 
 class NDFrameGroupBy(GroupBy):
diff --git a/pandas/core/groupby/groupby.py b/pandas/core/groupby/groupby.py
index 5acccbf688e30c..e31929434b5d60 100644
--- a/pandas/core/groupby/groupby.py
+++ b/pandas/core/groupby/groupby.py
@@ -8,35 +8,36 @@ class providing the base-class of operations.
 """
 
 import collections
+from contextlib import contextmanager
 import datetime
+from functools import partial, wraps
 import types
 import warnings
-from contextlib import contextmanager
-from functools import partial, wraps
 
 import numpy as np
 
-import pandas.core.algorithms as algorithms
-import pandas.core.common as com
-from pandas import compat
 from pandas._libs import Timestamp, groupby as libgroupby
+import pandas.compat as compat
 from pandas.compat import callable, range, set_function_name, zip
 from pandas.compat.numpy import function as nv
-from pandas.core.base import (
-    DataError, GroupByError, PandasObject, SelectionMixin, SpecificationError
-)
-from pandas.core.config import option_context
+from pandas.util._decorators import Appender, Substitution, cache_readonly
+from pandas.util._validators import validate_kwargs
+
 from pandas.core.dtypes.cast import maybe_downcast_to_dtype
 from pandas.core.dtypes.common import ensure_float, is_numeric_dtype, is_scalar
 from pandas.core.dtypes.missing import isna, notna
+
+import pandas.core.algorithms as algorithms
+from pandas.core.base import (
+    DataError, GroupByError, PandasObject, SelectionMixin, SpecificationError)
+import pandas.core.common as com
+from pandas.core.config import option_context
 from pandas.core.frame import DataFrame
 from pandas.core.generic import NDFrame
 from pandas.core.groupby import base
 from pandas.core.index import Index, MultiIndex
 from pandas.core.series import Series
 from pandas.core.sorting import get_group_index_sorter
-from pandas.util._decorators import Appender, Substitution, cache_readonly
-from pandas.util._validators import validate_kwargs
 
 _doc_template = """
 
diff --git a/pandas/core/groupby/grouper.py b/pandas/core/groupby/grouper.py
index cbe87040b81179..b49bc5ee5950f9 100644
--- a/pandas/core/groupby/grouper.py
+++ b/pandas/core/groupby/grouper.py
@@ -7,22 +7,24 @@
 
 import numpy as np
 
-import pandas.core.algorithms as algorithms
-import pandas.core.common as com
-from pandas import compat
+import pandas.compat as compat
 from pandas.compat import callable, zip
-from pandas.core.arrays import Categorical, ExtensionArray
+from pandas.util._decorators import cache_readonly
+
 from pandas.core.dtypes.common import (
     ensure_categorical, is_categorical_dtype, is_datetime64_dtype, is_hashable,
-    is_list_like, is_scalar, is_timedelta64_dtype
-)
+    is_list_like, is_scalar, is_timedelta64_dtype)
 from pandas.core.dtypes.generic import ABCSeries
+
+import pandas.core.algorithms as algorithms
+from pandas.core.arrays import Categorical, ExtensionArray
+import pandas.core.common as com
 from pandas.core.frame import DataFrame
 from pandas.core.groupby.ops import BaseGrouper
 from pandas.core.index import CategoricalIndex, Index, MultiIndex
 from pandas.core.series import Series
+
 from pandas.io.formats.printing import pprint_thing
-from pandas.util._decorators import cache_readonly
 
 
 class Grouper(object):
diff --git a/pandas/core/groupby/ops.py b/pandas/core/groupby/ops.py
index af22744c4feec2..390334a89cbfea 100644
--- a/pandas/core/groupby/ops.py
+++ b/pandas/core/groupby/ops.py
@@ -11,18 +11,20 @@
 
 import numpy as np
 
-import pandas.core.algorithms as algorithms
-import pandas.core.common as com
 from pandas._libs import NaT, groupby as libgroupby, iNaT, lib, reduction
 from pandas.compat import lzip, range, zip
-from pandas.core.base import SelectionMixin
+from pandas.util._decorators import cache_readonly
+
 from pandas.core.dtypes.common import (
     ensure_float64, ensure_int64, ensure_int64_or_float64, ensure_object,
     ensure_platform_int, is_bool_dtype, is_categorical_dtype, is_complex_dtype,
     is_datetime64_any_dtype, is_integer_dtype, is_numeric_dtype,
-    is_timedelta64_dtype, needs_i8_conversion
-)
+    is_timedelta64_dtype, needs_i8_conversion)
 from pandas.core.dtypes.missing import _maybe_fill, isna
+
+import pandas.core.algorithms as algorithms
+from pandas.core.base import SelectionMixin
+import pandas.core.common as com
 from pandas.core.frame import DataFrame
 from pandas.core.generic import NDFrame
 from pandas.core.groupby import base
@@ -30,9 +32,7 @@
 from pandas.core.series import Series
 from pandas.core.sorting import (
     compress_group_index, decons_obs_group_ids, get_flattened_iterator,
-    get_group_index, get_group_index_sorter, get_indexer_dict
-)
-from pandas.util._decorators import cache_readonly
+    get_group_index, get_group_index_sorter, get_indexer_dict)
 
 
 def generate_bins_generic(values, binner, closed):
diff --git a/pandas/core/indexes/range.py b/pandas/core/indexes/range.py
index 2b2f9ca51ce12c..cce5fda7dba281 100644
--- a/pandas/core/indexes/range.py
+++ b/pandas/core/indexes/range.py
@@ -1,25 +1,26 @@
-import operator
-import warnings
 from datetime import timedelta
+import operator
 from sys import getsizeof
+import warnings
 
 import numpy as np
 
-import pandas.core.common as com
-import pandas.core.indexes.base as ibase
-from pandas import compat
 from pandas._libs import index as libindex
+import pandas.compat as compat
 from pandas.compat import get_range_parameters, lrange, range
 from pandas.compat.numpy import function as nv
-from pandas.core import ops
+from pandas.util._decorators import Appender, cache_readonly
+
 from pandas.core.dtypes import concat as _concat
 from pandas.core.dtypes.common import (
-    is_int64_dtype, is_integer, is_scalar, is_timedelta64_dtype
-)
+    is_int64_dtype, is_integer, is_scalar, is_timedelta64_dtype)
 from pandas.core.dtypes.generic import ABCSeries, ABCTimedeltaIndex
+
+from pandas.core import ops
+import pandas.core.common as com
+import pandas.core.indexes.base as ibase
 from pandas.core.indexes.base import Index, _index_shared_docs
 from pandas.core.indexes.numeric import Int64Index
-from pandas.util._decorators import Appender, cache_readonly
 
 
 class RangeIndex(Int64Index):
diff --git a/pandas/core/series.py b/pandas/core/series.py
index 64d2e803dc8e19..6cc5acc4a61d0b 100644
--- a/pandas/core/series.py
+++ b/pandas/core/series.py
@@ -3,54 +3,47 @@
 """
 from __future__ import division
 
-import warnings
 from textwrap import dedent
+import warnings
 
 import numpy as np
 import numpy.ma as ma
 
-import pandas.core.algorithms as algorithms
-import pandas.core.common as com
-import pandas.core.indexes.base as ibase
-import pandas.core.nanops as nanops
-import pandas.core.ops as ops
-import pandas.io.formats.format as fmt
-import pandas.plotting._core as gfx
-from pandas import compat
 from pandas._libs import iNaT, index as libindex, lib, tslibs
+import pandas.compat as compat
 from pandas.compat import (
-    PY36, OrderedDict, StringIO, get_range_parameters, range, u, zip
-)
+    PY36, OrderedDict, StringIO, get_range_parameters, range, u, zip)
 from pandas.compat.numpy import function as nv
-from pandas.core import base, generic
-from pandas.core.accessor import CachedAccessor
-from pandas.core.arrays import ExtensionArray, SparseArray, period_array
-from pandas.core.arrays.categorical import Categorical, CategoricalAccessor
-from pandas.core.arrays.sparse import SparseAccessor
-from pandas.core.config import get_option
+from pandas.util._decorators import Appender, Substitution, deprecate
+from pandas.util._validators import validate_bool_kwarg
+
 from pandas.core.dtypes.cast import (
     construct_1d_arraylike_from_scalar, construct_1d_ndarray_preserving_na,
     construct_1d_object_array_from_listlike, infer_dtype_from_scalar,
     maybe_cast_to_datetime, maybe_cast_to_integer_array, maybe_castable,
-    maybe_convert_platform, maybe_upcast
-)
+    maybe_convert_platform, maybe_upcast)
 from pandas.core.dtypes.common import (
     _is_unorderable_exception, ensure_platform_int, is_bool,
     is_categorical_dtype, is_datetime64tz_dtype, is_datetimelike, is_dict_like,
     is_extension_array_dtype, is_extension_type, is_float_dtype, is_hashable,
     is_integer, is_integer_dtype, is_iterator, is_list_like, is_object_dtype,
-    is_scalar, is_string_like, is_timedelta64_dtype, pandas_dtype
-)
+    is_scalar, is_string_like, is_timedelta64_dtype, pandas_dtype)
 from pandas.core.dtypes.generic import (
-    ABCDataFrame, ABCIndexClass, ABCSeries, ABCSparseArray, ABCSparseSeries
-)
+    ABCDataFrame, ABCIndexClass, ABCSeries, ABCSparseArray, ABCSparseSeries)
 from pandas.core.dtypes.missing import (
-    isna, na_value_for_dtype, notna, remove_na_arraylike
-)
+    isna, na_value_for_dtype, notna, remove_na_arraylike)
+
+from pandas.core import algorithms, base, generic, nanops, ops
+from pandas.core.accessor import CachedAccessor
+from pandas.core.arrays import ExtensionArray, SparseArray, period_array
+from pandas.core.arrays.categorical import Categorical, CategoricalAccessor
+from pandas.core.arrays.sparse import SparseAccessor
+import pandas.core.common as com
+from pandas.core.config import get_option
 from pandas.core.index import (
-    Float64Index, Index, InvalidIndexError, MultiIndex, ensure_index
-)
+    Float64Index, Index, InvalidIndexError, MultiIndex, ensure_index)
 from pandas.core.indexes.accessors import CombinedDatetimelikeProperties
+import pandas.core.indexes.base as ibase
 from pandas.core.indexes.datetimes import DatetimeIndex
 from pandas.core.indexes.period import PeriodIndex
 from pandas.core.indexes.timedeltas import TimedeltaIndex
@@ -58,9 +51,10 @@
 from pandas.core.internals import SingleBlockManager
 from pandas.core.strings import StringMethods
 from pandas.core.tools.datetimes import to_datetime
+
+import pandas.io.formats.format as fmt
 from pandas.io.formats.terminal import get_terminal_size
-from pandas.util._decorators import Appender, Substitution, deprecate
-from pandas.util._validators import validate_bool_kwarg
+import pandas.plotting._core as gfx
 
 # pylint: disable=E1101,E1103
 # pylint: disable=W0703,W0622,W0613,W0201
diff --git a/pandas/io/clipboards.py b/pandas/io/clipboards.py
index 287a03c2e5728c..c6108f30a560a2 100644
--- a/pandas/io/clipboards.py
+++ b/pandas/io/clipboards.py
@@ -1,10 +1,13 @@
 """ io on the clipboard """
 import warnings
 
-from pandas import compat, get_option, option_context
+import pandas.compat as compat
 from pandas.compat import PY2, PY3, StringIO
+
 from pandas.core.dtypes.generic import ABCDataFrame
 
+from pandas import get_option, option_context
+
 
 def read_clipboard(sep=r'\s+', **kwargs):  # pragma: no cover
     r"""
diff --git a/pandas/io/common.py b/pandas/io/common.py
index 40247c4aebd1e9..155cf566b4c405 100644
--- a/pandas/io/common.py
+++ b/pandas/io/common.py
@@ -1,20 +1,21 @@
 """Common IO api utilities"""
 
 import codecs
+from contextlib import closing, contextmanager
 import csv
 import mmap
 import os
 import zipfile
-from contextlib import closing, contextmanager
 
-import pandas.core.common as com
-from pandas import compat
+import pandas.compat as compat
 from pandas.compat import BytesIO, StringIO, string_types, text_type
-from pandas.core.dtypes.common import is_file_like, is_number
-# compat
 from pandas.errors import (  # noqa
-    DtypeWarning, EmptyDataError, ParserError, ParserWarning
-)
+    DtypeWarning, EmptyDataError, ParserError, ParserWarning)
+
+from pandas.core.dtypes.common import is_file_like, is_number
+
+import pandas.core.common as com
+
 from pandas.io.formats.printing import pprint_thing
 
 # gh-12665: Alias for now and remove later.
diff --git a/pandas/io/excel.py b/pandas/io/excel.py
index c6a04b9bdee200..7a7b801f4ba4ac 100644
--- a/pandas/io/excel.py
+++ b/pandas/io/excel.py
@@ -2,15 +2,15 @@
 Module parse to/from Excel
 """
 
-import abc
-import os
-import warnings
 # ---------------------------------------------------------------------
 # ExcelFile class
+import abc
 from datetime import MINYEAR, date, datetime, time, timedelta
 from distutils.version import LooseVersion
 from io import UnsupportedOperation
+import os
 from textwrap import fill
+import warnings
 
 import numpy as np
 
@@ -18,21 +18,21 @@
 import pandas.compat as compat
 from pandas.compat import (
     OrderedDict, add_metaclass, lrange, map, range, reduce, string_types, u,
-    zip
-)
-from pandas.core import config
+    zip)
+from pandas.errors import EmptyDataError
+from pandas.util._decorators import Appender, deprecate_kwarg
+
 from pandas.core.dtypes.common import (
-    is_bool, is_float, is_integer, is_list_like
-)
+    is_bool, is_float, is_integer, is_list_like)
+
+from pandas.core import config
 from pandas.core.frame import DataFrame
-from pandas.errors import EmptyDataError
+
 from pandas.io.common import (
     _NA_VALUES, _is_url, _stringify_path, _urlopen, _validate_header_arg,
-    get_filepath_or_buffer
-)
+    get_filepath_or_buffer)
 from pandas.io.formats.printing import pprint_thing
 from pandas.io.parsers import TextParser
-from pandas.util._decorators import Appender, deprecate_kwarg
 
 __all__ = ["read_excel", "ExcelWriter", "ExcelFile"]
 
diff --git a/pandas/io/feather_format.py b/pandas/io/feather_format.py
index 436c16839ffc24..8d2715fe5beedd 100644
--- a/pandas/io/feather_format.py
+++ b/pandas/io/feather_format.py
@@ -2,8 +2,10 @@
 
 from distutils.version import LooseVersion
 
-from pandas import DataFrame, Int64Index, RangeIndex
 from pandas.compat import range
+
+from pandas import DataFrame, Int64Index, RangeIndex
+
 from pandas.io.common import _stringify_path
 
 
diff --git a/pandas/io/html.py b/pandas/io/html.py
index a1d3f4589ba352..4f887b69646ee9 100644
--- a/pandas/io/html.py
+++ b/pandas/io/html.py
@@ -3,19 +3,22 @@
 
 """
 
+from distutils.version import LooseVersion
 import numbers
 import os
 import re
-from distutils.version import LooseVersion
 
-import pandas.core.common as com
-from pandas import Series, compat
+import pandas.compat as compat
 from pandas.compat import (
     binary_type, iteritems, lmap, lrange, raise_with_traceback, string_types,
-    u
-)
-from pandas.core.dtypes.common import is_list_like
+    u)
 from pandas.errors import EmptyDataError
+
+from pandas.core.dtypes.common import is_list_like
+
+from pandas import Series
+import pandas.core.common as com
+
 from pandas.io.common import _is_url, _validate_header_arg, urlopen
 from pandas.io.formats.printing import pprint_thing
 from pandas.io.parsers import TextParser
diff --git a/pandas/io/packers.py b/pandas/io/packers.py
index 764e27a60abb50..ea673101e90b37 100644
--- a/pandas/io/packers.py
+++ b/pandas/io/packers.py
@@ -38,35 +38,36 @@
 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 """
 
-import os
-import warnings
 from datetime import date, datetime, timedelta
+import os
 from textwrap import dedent
+import warnings
 
-import numpy as np
 from dateutil.parser import parse
+import numpy as np
+
+import pandas.compat as compat
+from pandas.compat import u, u_safe
+from pandas.errors import PerformanceWarning
+from pandas.util._move import (
+    BadMove as _BadMove, move_into_mutable_buffer as _move_into_mutable_buffer)
+
+from pandas.core.dtypes.common import (
+    is_categorical_dtype, is_object_dtype, needs_i8_conversion, pandas_dtype)
 
 from pandas import (  # noqa:F401
     Categorical, CategoricalIndex, DataFrame, DatetimeIndex, Float64Index,
     Index, Int64Index, Interval, IntervalIndex, MultiIndex, NaT, Panel, Period,
-    PeriodIndex, RangeIndex, Series, TimedeltaIndex, Timestamp, compat
-)
-from pandas.compat import u, u_safe
+    PeriodIndex, RangeIndex, Series, TimedeltaIndex, Timestamp)
 from pandas.core import internals
 from pandas.core.arrays import IntervalArray, PeriodArray
 from pandas.core.arrays.sparse import BlockIndex, IntIndex
-from pandas.core.dtypes.common import (
-    is_categorical_dtype, is_object_dtype, needs_i8_conversion, pandas_dtype
-)
 from pandas.core.generic import NDFrame
 from pandas.core.internals import BlockManager, _safe_reshape, make_block
 from pandas.core.sparse.api import SparseDataFrame, SparseSeries
-from pandas.errors import PerformanceWarning
+
 from pandas.io.common import _stringify_path, get_filepath_or_buffer
 from pandas.io.msgpack import ExtType, Packer as _Packer, Unpacker as _Unpacker
-from pandas.util._move import (
-    BadMove as _BadMove, move_into_mutable_buffer as _move_into_mutable_buffer
-)
 
 # check which compression libs we have installed
 try:
diff --git a/pandas/io/parquet.py b/pandas/io/parquet.py
index aef1d84a19bc75..2c75f46385e868 100644
--- a/pandas/io/parquet.py
+++ b/pandas/io/parquet.py
@@ -3,9 +3,11 @@
 from distutils.version import LooseVersion
 from warnings import catch_warnings
 
-import pandas.core.common as com
-from pandas import DataFrame, Int64Index, RangeIndex, get_option
 from pandas.compat import string_types
+
+from pandas import DataFrame, Int64Index, RangeIndex, get_option
+import pandas.core.common as com
+
 from pandas.io.common import get_filepath_or_buffer, is_s3_url
 
 
diff --git a/pandas/io/parsers.py b/pandas/io/parsers.py
index 8dd50fceb4efb8..cd9d3ccb79af84 100755
--- a/pandas/io/parsers.py
+++ b/pandas/io/parsers.py
@@ -3,49 +3,48 @@
 """
 from __future__ import print_function
 
+from collections import defaultdict
 import csv
 import datetime
 import re
 import sys
-import warnings
-from collections import defaultdict
 from textwrap import fill
+import warnings
 
 import numpy as np
 
 import pandas._libs.lib as lib
 import pandas._libs.ops as libops
 import pandas._libs.parsers as parsers
-import pandas.core.common as com
-from pandas import compat
 from pandas._libs.tslibs import parsing
+import pandas.compat as compat
 from pandas.compat import (
-    PY3, StringIO, lrange, lzip, map, range, string_types, u, zip
-)
-from pandas.core import algorithms
-from pandas.core.arrays import Categorical
+    PY3, StringIO, lrange, lzip, map, range, string_types, u, zip)
+from pandas.errors import EmptyDataError, ParserError, ParserWarning
+from pandas.util._decorators import Appender
+
 from pandas.core.dtypes.cast import astype_nansafe
 from pandas.core.dtypes.common import (
     ensure_object, is_categorical_dtype, is_dtype_equal, is_float, is_integer,
     is_integer_dtype, is_list_like, is_object_dtype, is_scalar,
-    is_string_dtype
-)
+    is_string_dtype)
 from pandas.core.dtypes.dtypes import CategoricalDtype
 from pandas.core.dtypes.missing import isna
+
+from pandas.core import algorithms
+from pandas.core.arrays import Categorical
+import pandas.core.common as com
 from pandas.core.frame import DataFrame
 from pandas.core.index import (
-    Index, MultiIndex, RangeIndex, ensure_index_from_sequences
-)
+    Index, MultiIndex, RangeIndex, ensure_index_from_sequences)
 from pandas.core.series import Series
 from pandas.core.tools import datetimes as tools
-from pandas.errors import EmptyDataError, ParserError, ParserWarning
+
 from pandas.io.common import (
     _NA_VALUES, BaseIterator, UnicodeReader, UTF8Recoder, _get_handle,
     _infer_compression, _validate_header_arg, get_filepath_or_buffer,
-    is_file_like
-)
+    is_file_like)
 from pandas.io.date_converters import generic_parser
-from pandas.util._decorators import Appender
 
 # BOM character (byte order mark)
 # This exists at the beginning of a file to indicate endianness
diff --git a/pandas/io/pickle.py b/pandas/io/pickle.py
index 4e71462f4e3310..c89d1df8ee64ba 100644
--- a/pandas/io/pickle.py
+++ b/pandas/io/pickle.py
@@ -5,7 +5,9 @@
 from numpy.lib.format import read_array, write_array
 
 from pandas.compat import PY3, BytesIO, cPickle as pkl, pickle_compat as pc
+
 from pandas.core.dtypes.common import _NS_DTYPE, is_datetime64_dtype
+
 from pandas.io.common import _get_handle, _stringify_path
 
 
diff --git a/pandas/io/pytables.py b/pandas/io/pytables.py
index 0830aece8c6f4c..56b63fddd96ad5 100644
--- a/pandas/io/pytables.py
+++ b/pandas/io/pytables.py
@@ -5,46 +5,45 @@
 """
 
 import copy
+from datetime import date, datetime
+from distutils.version import LooseVersion
 import itertools
 import os
 import re
 import time
 import warnings
-from datetime import date, datetime
-from distutils.version import LooseVersion
 
 import numpy as np
 
-import pandas.core.common as com
-from pandas import (
-    DataFrame, DatetimeIndex, Index, Int64Index, MultiIndex, Panel,
-    PeriodIndex, Series, SparseDataFrame, SparseSeries, TimedeltaIndex, compat,
-    concat, isna, to_datetime
-)
 from pandas._libs import algos, lib, writers as libwriters
 from pandas._libs.tslibs import timezones
 from pandas.compat import PY3, filter, lrange, range, string_types
+from pandas.errors import PerformanceWarning
+
+from pandas.core.dtypes.common import (
+    ensure_int64, ensure_object, ensure_platform_int, is_categorical_dtype,
+    is_datetime64_dtype, is_datetime64tz_dtype, is_list_like,
+    is_timedelta64_dtype)
+from pandas.core.dtypes.missing import array_equivalent
+
+from pandas import (
+    DataFrame, DatetimeIndex, Index, Int64Index, MultiIndex, Panel,
+    PeriodIndex, Series, SparseDataFrame, SparseSeries, TimedeltaIndex, compat,
+    concat, isna, to_datetime)
 from pandas.core import config
 from pandas.core.algorithms import match, unique
 from pandas.core.arrays.categorical import (
-    Categorical, _factorize_from_iterables
-)
+    Categorical, _factorize_from_iterables)
 from pandas.core.arrays.sparse import BlockIndex, IntIndex
 from pandas.core.base import StringMixin
+import pandas.core.common as com
 from pandas.core.computation.pytables import Expr, maybe_expression
 from pandas.core.config import get_option
-from pandas.core.dtypes.common import (
-    ensure_int64, ensure_object, ensure_platform_int, is_categorical_dtype,
-    is_datetime64_dtype, is_datetime64tz_dtype, is_list_like,
-    is_timedelta64_dtype
-)
-from pandas.core.dtypes.missing import array_equivalent
 from pandas.core.index import ensure_index
 from pandas.core.internals import (
     BlockManager, _block2d_to_blocknd, _block_shape, _factor_indexer,
-    make_block
-)
-from pandas.errors import PerformanceWarning
+    make_block)
+
 from pandas.io.common import _stringify_path
 from pandas.io.formats.printing import adjoin, pprint_thing
 
diff --git a/pandas/io/sas/sas_xport.py b/pandas/io/sas/sas_xport.py
index c326580487b094..6a38e3d2eb783d 100644
--- a/pandas/io/sas/sas_xport.py
+++ b/pandas/io/sas/sas_xport.py
@@ -8,16 +8,18 @@
 https://support.sas.com/techsup/technote/ts140.pdf
 """
 
+from datetime import datetime
 import struct
 import warnings
-from datetime import datetime
 
 import numpy as np
 
+from pandas.util._decorators import Appender
+
 import pandas as pd
 from pandas import compat
+
 from pandas.io.common import BaseIterator, get_filepath_or_buffer
-from pandas.util._decorators import Appender
 
 _correct_line1 = ("HEADER RECORD*******LIBRARY HEADER RECORD!!!!!!!"
                   "000000000000000000000000000000  ")
diff --git a/pandas/io/sas/sasreader.py b/pandas/io/sas/sasreader.py
index d72996a8e6157a..2da3775d5a6a74 100644
--- a/pandas/io/sas/sasreader.py
+++ b/pandas/io/sas/sasreader.py
@@ -2,6 +2,7 @@
 Read SAS sas7bdat or xport files.
 """
 from pandas import compat
+
 from pandas.io.common import _stringify_path
 
 
diff --git a/pandas/io/sql.py b/pandas/io/sql.py
index 3876792d6226fe..00fbc35ed1e7db 100644
--- a/pandas/io/sql.py
+++ b/pandas/io/sql.py
@@ -6,24 +6,24 @@
 
 from __future__ import division, print_function
 
-import re
-import warnings
 from contextlib import contextmanager
 from datetime import date, datetime, time
+import re
+import warnings
 
 import numpy as np
 
 import pandas._libs.lib as lib
 from pandas.compat import (
-    map, raise_with_traceback, string_types, text_type, zip
-)
-from pandas.core.api import DataFrame, Series
-from pandas.core.base import PandasObject
+    map, raise_with_traceback, string_types, text_type, zip)
+
 from pandas.core.dtypes.common import (
-    is_datetime64tz_dtype, is_dict_like, is_list_like
-)
+    is_datetime64tz_dtype, is_dict_like, is_list_like)
 from pandas.core.dtypes.dtypes import DatetimeTZDtype
 from pandas.core.dtypes.missing import isna
+
+from pandas.core.api import DataFrame, Series
+from pandas.core.base import PandasObject
 from pandas.core.tools.datetimes import to_datetime
 
 
diff --git a/pandas/io/stata.py b/pandas/io/stata.py
index 00d1a925879302..df0d47b063411f 100644
--- a/pandas/io/stata.py
+++ b/pandas/io/stata.py
@@ -10,33 +10,33 @@
 http://www.statsmodels.org/devel/
 """
 
+from collections import OrderedDict
 import datetime
 import struct
 import sys
 import warnings
-from collections import OrderedDict
 
-import numpy as np
 from dateutil.relativedelta import relativedelta
+import numpy as np
 
-from pandas import DatetimeIndex, compat, isna, to_datetime, to_timedelta
 from pandas._libs.lib import infer_dtype
 from pandas._libs.tslibs import NaT, Timestamp
 from pandas._libs.writers import max_len_string_array
 from pandas.compat import (
-    BytesIO, lmap, lrange, lzip, range, string_types, text_type, zip
-)
+    BytesIO, lmap, lrange, lzip, range, string_types, text_type, zip)
+from pandas.util._decorators import Appender, deprecate_kwarg
+
+from pandas.core.dtypes.common import (
+    ensure_object, is_categorical_dtype, is_datetime64_dtype)
+
+from pandas import DatetimeIndex, compat, isna, to_datetime, to_timedelta
 from pandas.core.arrays import Categorical
 from pandas.core.base import StringMixin
-from pandas.core.dtypes.common import (
-    ensure_object, is_categorical_dtype, is_datetime64_dtype
-)
 from pandas.core.frame import DataFrame
 from pandas.core.series import Series
+
 from pandas.io.common import (
-    BaseIterator, _stringify_path, get_filepath_or_buffer
-)
-from pandas.util._decorators import Appender, deprecate_kwarg
+    BaseIterator, _stringify_path, get_filepath_or_buffer)
 
 _version_error = ("Version of given Stata file is not 104, 105, 108, "
                   "111 (Stata 7SE), 113 (Stata 8/9), 114 (Stata 10/11), "
diff --git a/pandas/tests/arrays/categorical/test_analytics.py b/pandas/tests/arrays/categorical/test_analytics.py
index 18cce6573817c0..0f292a457bbc25 100644
--- a/pandas/tests/arrays/categorical/test_analytics.py
+++ b/pandas/tests/arrays/categorical/test_analytics.py
@@ -5,10 +5,11 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
-from pandas import Categorical, Index, Series
 from pandas.compat import PYPY
 
+from pandas import Categorical, Index, Series
+import pandas.util.testing as tm
+
 
 class TestCategoricalAnalytics(object):
 
diff --git a/pandas/tests/arrays/categorical/test_api.py b/pandas/tests/arrays/categorical/test_api.py
index 1deef4762be266..54de398473d522 100644
--- a/pandas/tests/arrays/categorical/test_api.py
+++ b/pandas/tests/arrays/categorical/test_api.py
@@ -3,10 +3,10 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Categorical, CategoricalIndex, DataFrame, Index, Series
 from pandas.core.arrays.categorical import _recode_for_categories
 from pandas.tests.arrays.categorical.common import TestCategorical
+import pandas.util.testing as tm
 
 
 class TestCategoricalAPI(object):
diff --git a/pandas/tests/arrays/categorical/test_constructors.py b/pandas/tests/arrays/categorical/test_constructors.py
index b53fd0aa80344d..8bd245d2aabae0 100644
--- a/pandas/tests/arrays/categorical/test_constructors.py
+++ b/pandas/tests/arrays/categorical/test_constructors.py
@@ -5,15 +5,15 @@
 import numpy as np
 import pytest
 
+from pandas.core.dtypes.common import is_float_dtype, is_integer_dtype
+from pandas.core.dtypes.dtypes import CategoricalDtype
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
     Categorical, CategoricalIndex, DatetimeIndex, Index, Interval,
     IntervalIndex, NaT, Series, Timestamp, date_range, period_range,
-    timedelta_range
-)
-from pandas.core.dtypes.common import is_float_dtype, is_integer_dtype
-from pandas.core.dtypes.dtypes import CategoricalDtype
+    timedelta_range)
+import pandas.util.testing as tm
 
 
 class TestCategoricalConstructors(object):
diff --git a/pandas/tests/arrays/categorical/test_dtypes.py b/pandas/tests/arrays/categorical/test_dtypes.py
index 7d4824fe7d18a6..491a7867fee719 100644
--- a/pandas/tests/arrays/categorical/test_dtypes.py
+++ b/pandas/tests/arrays/categorical/test_dtypes.py
@@ -2,11 +2,13 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
-from pandas import Categorical, CategoricalIndex, Index, Series, Timestamp
 from pandas.compat import long
+
 from pandas.core.dtypes.dtypes import CategoricalDtype
 
+from pandas import Categorical, CategoricalIndex, Index, Series, Timestamp
+import pandas.util.testing as tm
+
 
 class TestCategoricalDtypes(object):
 
diff --git a/pandas/tests/arrays/categorical/test_indexing.py b/pandas/tests/arrays/categorical/test_indexing.py
index d74a7d5d2ed5d4..a54ee7381f9ebd 100644
--- a/pandas/tests/arrays/categorical/test_indexing.py
+++ b/pandas/tests/arrays/categorical/test_indexing.py
@@ -3,10 +3,10 @@
 import numpy as np
 import pytest
 
-import pandas.core.common as com
-import pandas.util.testing as tm
 from pandas import Categorical, CategoricalIndex, Index, PeriodIndex, Series
+import pandas.core.common as com
 from pandas.tests.arrays.categorical.common import TestCategorical
+import pandas.util.testing as tm
 
 
 class TestCategoricalIndexingWithFactor(TestCategorical):
diff --git a/pandas/tests/arrays/categorical/test_operators.py b/pandas/tests/arrays/categorical/test_operators.py
index a4b39846cbfaf1..ce15ebfb281f27 100644
--- a/pandas/tests/arrays/categorical/test_operators.py
+++ b/pandas/tests/arrays/categorical/test_operators.py
@@ -4,9 +4,9 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import Categorical, DataFrame, Series, date_range
 from pandas.tests.arrays.categorical.common import TestCategorical
+import pandas.util.testing as tm
 
 
 class TestCategoricalOpsWithFactor(TestCategorical):
diff --git a/pandas/tests/arrays/categorical/test_repr.py b/pandas/tests/arrays/categorical/test_repr.py
index 3c830ee6f6da53..5f71d0148ee88f 100644
--- a/pandas/tests/arrays/categorical/test_repr.py
+++ b/pandas/tests/arrays/categorical/test_repr.py
@@ -2,11 +2,11 @@
 
 import numpy as np
 
+from pandas.compat import PY3, u
+
 from pandas import (
     Categorical, CategoricalIndex, Series, date_range, period_range,
-    timedelta_range
-)
-from pandas.compat import PY3, u
+    timedelta_range)
 from pandas.core.config import option_context
 from pandas.tests.arrays.categorical.common import TestCategorical
 
diff --git a/pandas/tests/arrays/categorical/test_subclass.py b/pandas/tests/arrays/categorical/test_subclass.py
index 08ebb7d1b05f75..7e90f8d51a3efe 100644
--- a/pandas/tests/arrays/categorical/test_subclass.py
+++ b/pandas/tests/arrays/categorical/test_subclass.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
-import pandas.util.testing as tm
 from pandas import Categorical
+import pandas.util.testing as tm
 
 
 class TestCategoricalSubclassing(object):
diff --git a/pandas/tests/arrays/interval/test_interval.py b/pandas/tests/arrays/interval/test_interval.py
index ff69b68f1117c3..9a191dda3a73a5 100644
--- a/pandas/tests/arrays/interval/test_interval.py
+++ b/pandas/tests/arrays/interval/test_interval.py
@@ -2,9 +2,9 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Index, IntervalIndex, date_range, timedelta_range
 from pandas.core.arrays import IntervalArray
+import pandas.util.testing as tm
 
 
 @pytest.fixture(params=[
diff --git a/pandas/tests/arrays/interval/test_ops.py b/pandas/tests/arrays/interval/test_ops.py
index 7000ff0f0c3f6f..45bf465577aceb 100644
--- a/pandas/tests/arrays/interval/test_ops.py
+++ b/pandas/tests/arrays/interval/test_ops.py
@@ -2,9 +2,9 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Interval, IntervalIndex, Timedelta, Timestamp
 from pandas.core.arrays import IntervalArray
+import pandas.util.testing as tm
 
 
 @pytest.fixture(params=[IntervalArray, IntervalIndex])
diff --git a/pandas/tests/arrays/sparse/test_arithmetics.py b/pandas/tests/arrays/sparse/test_arithmetics.py
index 2aa24fff3d1d7c..42a29654b44d51 100644
--- a/pandas/tests/arrays/sparse/test_arithmetics.py
+++ b/pandas/tests/arrays/sparse/test_arithmetics.py
@@ -4,8 +4,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas.core.sparse.api import SparseDtype
+import pandas.util.testing as tm
 
 
 class TestSparseArrayArithmetics(object):
diff --git a/pandas/tests/arrays/sparse/test_array.py b/pandas/tests/arrays/sparse/test_array.py
index 45c23735a986bc..852c4fb9105601 100644
--- a/pandas/tests/arrays/sparse/test_array.py
+++ b/pandas/tests/arrays/sparse/test_array.py
@@ -3,15 +3,16 @@
 import warnings
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
-import pandas as pd
-import pandas.util._test_decorators as td
-import pandas.util.testing as tm
 from pandas._libs.sparse import IntIndex
 from pandas.compat import range
+import pandas.util._test_decorators as td
+
+import pandas as pd
 from pandas.core.sparse.api import SparseArray, SparseDtype, SparseSeries
+import pandas.util.testing as tm
 from pandas.util.testing import assert_almost_equal
 
 
diff --git a/pandas/tests/arrays/sparse/test_dtype.py b/pandas/tests/arrays/sparse/test_dtype.py
index d3e2116882739f..75fc325b07a082 100644
--- a/pandas/tests/arrays/sparse/test_dtype.py
+++ b/pandas/tests/arrays/sparse/test_dtype.py
@@ -2,8 +2,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas.core.sparse.api import SparseDtype
+import pandas.util.testing as tm
 
 
 @pytest.mark.parametrize("dtype, fill_value", [
diff --git a/pandas/tests/arrays/sparse/test_libsparse.py b/pandas/tests/arrays/sparse/test_libsparse.py
index e6ebd92c6ffdc5..cbad7e8e9136d7 100644
--- a/pandas/tests/arrays/sparse/test_libsparse.py
+++ b/pandas/tests/arrays/sparse/test_libsparse.py
@@ -5,9 +5,10 @@
 
 import pandas._libs.sparse as splib
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
 from pandas import Series
 from pandas.core.arrays.sparse import BlockIndex, IntIndex, _make_index
+import pandas.util.testing as tm
 
 TEST_LENGTH = 20
 
diff --git a/pandas/tests/arrays/test_period.py b/pandas/tests/arrays/test_period.py
index dcbb0d4048b0f8..40bdd4f1aaa5c6 100644
--- a/pandas/tests/arrays/test_period.py
+++ b/pandas/tests/arrays/test_period.py
@@ -1,14 +1,16 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
 from pandas._libs.tslibs import iNaT
 from pandas._libs.tslibs.period import IncompatibleFrequency
-from pandas.core.arrays import PeriodArray, period_array
+
 from pandas.core.dtypes.common import pandas_dtype
 from pandas.core.dtypes.dtypes import PeriodDtype
 
+import pandas as pd
+from pandas.core.arrays import PeriodArray, period_array
+import pandas.util.testing as tm
+
 # ----------------------------------------------------------------------------
 # Constructors
 
diff --git a/pandas/tests/extension/arrow/bool.py b/pandas/tests/extension/arrow/bool.py
index e6f997b01aad20..f8e357e1622326 100644
--- a/pandas/tests/extension/arrow/bool.py
+++ b/pandas/tests/extension/arrow/bool.py
@@ -13,8 +13,7 @@
 
 import pandas as pd
 from pandas.api.extensions import (
-    ExtensionArray, ExtensionDtype, register_extension_dtype, take
-)
+    ExtensionArray, ExtensionDtype, register_extension_dtype, take)
 
 
 @register_extension_dtype
diff --git a/pandas/tests/extension/base/constructors.py b/pandas/tests/extension/base/constructors.py
index fdd2b99d9b3c76..076be53a4a72f7 100644
--- a/pandas/tests/extension/base/constructors.py
+++ b/pandas/tests/extension/base/constructors.py
@@ -1,8 +1,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas.core.internals import ExtensionBlock
+import pandas.util.testing as tm
 
 from .base import BaseExtensionTests
 
diff --git a/pandas/tests/extension/base/interface.py b/pandas/tests/extension/base/interface.py
index 91b1b87a9d7ea6..00a480d311b58f 100644
--- a/pandas/tests/extension/base/interface.py
+++ b/pandas/tests/extension/base/interface.py
@@ -1,10 +1,12 @@
 import numpy as np
 
-import pandas as pd
 from pandas.compat import StringIO
+
 from pandas.core.dtypes.common import is_extension_array_dtype
 from pandas.core.dtypes.dtypes import ExtensionDtype
 
+import pandas as pd
+
 from .base import BaseExtensionTests
 
 
diff --git a/pandas/tests/extension/decimal/array.py b/pandas/tests/extension/decimal/array.py
index e47b8049ae65c1..c14bfa359bc64b 100644
--- a/pandas/tests/extension/decimal/array.py
+++ b/pandas/tests/extension/decimal/array.py
@@ -5,9 +5,10 @@
 
 import numpy as np
 
+from pandas.core.dtypes.base import ExtensionDtype
+
 import pandas as pd
 from pandas.core.arrays import ExtensionArray, ExtensionScalarOpsMixin
-from pandas.core.dtypes.base import ExtensionDtype
 
 
 class DecimalDtype(ExtensionDtype):
diff --git a/pandas/tests/extension/decimal/test_decimal.py b/pandas/tests/extension/decimal/test_decimal.py
index 59e77c3f0f3f3f..1c9beefe9e5428 100644
--- a/pandas/tests/extension/decimal/test_decimal.py
+++ b/pandas/tests/extension/decimal/test_decimal.py
@@ -5,9 +5,9 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import compat
 from pandas.tests.extension import base
+import pandas.util.testing as tm
 
 from .array import DecimalArray, DecimalDtype, make_data, to_decimal
 
diff --git a/pandas/tests/extension/json/array.py b/pandas/tests/extension/json/array.py
index 75b0f6b02edadb..2c6e74fda8a0e6 100644
--- a/pandas/tests/extension/json/array.py
+++ b/pandas/tests/extension/json/array.py
@@ -19,9 +19,10 @@
 
 import numpy as np
 
+from pandas.core.dtypes.base import ExtensionDtype
+
 from pandas import compat
 from pandas.core.arrays import ExtensionArray
-from pandas.core.dtypes.base import ExtensionDtype
 
 
 class JSONDtype(ExtensionDtype):
diff --git a/pandas/tests/extension/json/test_json.py b/pandas/tests/extension/json/test_json.py
index d6528e30855272..778432376e092c 100644
--- a/pandas/tests/extension/json/test_json.py
+++ b/pandas/tests/extension/json/test_json.py
@@ -3,10 +3,11 @@
 
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
 from pandas.compat import PY2, PY36
+
+import pandas as pd
 from pandas.tests.extension import base
+import pandas.util.testing as tm
 
 from .array import JSONArray, JSONDtype, make_data
 
diff --git a/pandas/tests/extension/test_categorical.py b/pandas/tests/extension/test_categorical.py
index b5ded1890ae649..65e6a15dd8df05 100644
--- a/pandas/tests/extension/test_categorical.py
+++ b/pandas/tests/extension/test_categorical.py
@@ -19,10 +19,10 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import Categorical
 from pandas.api.types import CategoricalDtype
 from pandas.tests.extension import base
+import pandas.util.testing as tm
 
 
 def make_data():
diff --git a/pandas/tests/extension/test_common.py b/pandas/tests/extension/test_common.py
index 8a026a0c382839..2bc4bf5df22984 100644
--- a/pandas/tests/extension/test_common.py
+++ b/pandas/tests/extension/test_common.py
@@ -1,12 +1,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas.core.arrays import ExtensionArray
 from pandas.core.dtypes import dtypes
 from pandas.core.dtypes.common import is_extension_array_dtype
 
+import pandas as pd
+from pandas.core.arrays import ExtensionArray
+import pandas.util.testing as tm
+
 
 class DummyDtype(dtypes.ExtensionDtype):
     pass
diff --git a/pandas/tests/extension/test_integer.py b/pandas/tests/extension/test_integer.py
index 680cf83c64b9ed..efee6473898841 100644
--- a/pandas/tests/extension/test_integer.py
+++ b/pandas/tests/extension/test_integer.py
@@ -16,13 +16,13 @@
 import numpy as np
 import pytest
 
+from pandas.core.dtypes.common import is_extension_array_dtype
+
 import pandas as pd
 from pandas.core.arrays import integer_array
 from pandas.core.arrays.integer import (
     Int8Dtype, Int16Dtype, Int32Dtype, Int64Dtype, UInt8Dtype, UInt16Dtype,
-    UInt32Dtype, UInt64Dtype
-)
-from pandas.core.dtypes.common import is_extension_array_dtype
+    UInt32Dtype, UInt64Dtype)
 from pandas.tests.extension import base
 
 
diff --git a/pandas/tests/extension/test_interval.py b/pandas/tests/extension/test_interval.py
index 3ffb88ef302e9f..3154f34434ce2c 100644
--- a/pandas/tests/extension/test_interval.py
+++ b/pandas/tests/extension/test_interval.py
@@ -16,11 +16,12 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
+from pandas.core.dtypes.dtypes import IntervalDtype
+
 from pandas import Interval
 from pandas.core.arrays import IntervalArray
-from pandas.core.dtypes.dtypes import IntervalDtype
 from pandas.tests.extension import base
+import pandas.util.testing as tm
 
 
 def make_data():
diff --git a/pandas/tests/extension/test_period.py b/pandas/tests/extension/test_period.py
index 6f59cbb66a145d..83f30aed88e651 100644
--- a/pandas/tests/extension/test_period.py
+++ b/pandas/tests/extension/test_period.py
@@ -1,12 +1,14 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
 from pandas._libs.tslib import iNaT
-from pandas.core.arrays import PeriodArray
+
 from pandas.core.dtypes.dtypes import PeriodDtype
+
+import pandas as pd
+from pandas.core.arrays import PeriodArray
 from pandas.tests.extension import base
+import pandas.util.testing as tm
 
 
 @pytest.fixture
diff --git a/pandas/tests/indexes/common.py b/pandas/tests/indexes/common.py
index bec969020559c6..468b1610a91423 100644
--- a/pandas/tests/indexes/common.py
+++ b/pandas/tests/indexes/common.py
@@ -3,19 +3,21 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import (
-    CategoricalIndex, DatetimeIndex, Float64Index, Index, Int64Index,
-    IntervalIndex, MultiIndex, PeriodIndex, RangeIndex, Series, TimedeltaIndex,
-    UInt64Index, compat, isna
-)
 from pandas._libs.tslib import iNaT
+import pandas.compat as compat
 from pandas.compat import PY3
+
 from pandas.core.dtypes.common import needs_i8_conversion
 from pandas.core.dtypes.dtypes import CategoricalDtype
+
+import pandas as pd
+from pandas import (
+    CategoricalIndex, DatetimeIndex, Float64Index, Index, Int64Index,
+    IntervalIndex, MultiIndex, PeriodIndex, RangeIndex, Series, TimedeltaIndex,
+    UInt64Index, isna)
 from pandas.core.indexes.base import InvalidIndexError
 from pandas.core.indexes.datetimelike import DatetimeIndexOpsMixin
+import pandas.util.testing as tm
 
 
 class Base(object):
diff --git a/pandas/tests/indexes/conftest.py b/pandas/tests/indexes/conftest.py
index 4a2a4a7deb5ccf..8cfed33a96ac5b 100644
--- a/pandas/tests/indexes/conftest.py
+++ b/pandas/tests/indexes/conftest.py
@@ -1,10 +1,11 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
 from pandas.compat import long, lzip
+
+import pandas as pd
 from pandas.core.indexes.api import Index, MultiIndex
+import pandas.util.testing as tm
 
 
 @pytest.fixture(params=[tm.makeUnicodeIndex(100),
diff --git a/pandas/tests/indexes/datetimes/test_arithmetic.py b/pandas/tests/indexes/datetimes/test_arithmetic.py
index 038c4f786f69f9..de51120baeb582 100644
--- a/pandas/tests/indexes/datetimes/test_arithmetic.py
+++ b/pandas/tests/indexes/datetimes/test_arithmetic.py
@@ -4,10 +4,11 @@
 import pytest
 import pytz
 
+from pandas.errors import NullFrequencyError
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DatetimeIndex, Series, date_range
-from pandas.errors import NullFrequencyError
+import pandas.util.testing as tm
 
 
 class TestDatetimeIndexArithmetic(object):
diff --git a/pandas/tests/indexes/datetimes/test_astype.py b/pandas/tests/indexes/datetimes/test_astype.py
index 8895624d74e898..a9cfc551e073b1 100644
--- a/pandas/tests/indexes/datetimes/test_astype.py
+++ b/pandas/tests/indexes/datetimes/test_astype.py
@@ -1,17 +1,16 @@
 from datetime import datetime
 
 import dateutil
+from dateutil.tz import tzlocal
 import numpy as np
 import pytest
 import pytz
-from dateutil.tz import tzlocal
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
     DatetimeIndex, Index, Int64Index, NaT, Period, Series, Timestamp,
-    date_range
-)
+    date_range)
+import pandas.util.testing as tm
 
 
 class TestDatetimeIndex(object):
diff --git a/pandas/tests/indexes/datetimes/test_construction.py b/pandas/tests/indexes/datetimes/test_construction.py
index 2fc3e29a47b20b..7a251a8ecfb28f 100644
--- a/pandas/tests/indexes/datetimes/test_construction.py
+++ b/pandas/tests/indexes/datetimes/test_construction.py
@@ -6,14 +6,14 @@
 import pytest
 import pytz
 
+from pandas._libs.tslib import OutOfBoundsDatetime
+from pandas._libs.tslibs import conversion
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
     DatetimeIndex, Index, Timestamp, date_range, datetime, offsets,
-    to_datetime
-)
-from pandas._libs.tslib import OutOfBoundsDatetime
-from pandas._libs.tslibs import conversion
+    to_datetime)
+import pandas.util.testing as tm
 
 
 class TestDatetimeIndex(object):
diff --git a/pandas/tests/indexes/datetimes/test_date_range.py b/pandas/tests/indexes/datetimes/test_date_range.py
index 450d7643bfbd5b..b6bab272c8c0aa 100644
--- a/pandas/tests/indexes/datetimes/test_date_range.py
+++ b/pandas/tests/indexes/datetimes/test_date_range.py
@@ -9,17 +9,17 @@
 import pytz
 from pytz import timezone
 
-import pandas as pd
-import pandas.util._test_decorators as td
-import pandas.util.testing as tm
-from pandas import (
-    DatetimeIndex, Timestamp, bdate_range, compat, date_range, offsets
-)
+import pandas.compat as compat
 from pandas.errors import OutOfBoundsDatetime
+import pandas.util._test_decorators as td
+
+import pandas as pd
+from pandas import DatetimeIndex, Timestamp, bdate_range, date_range, offsets
 from pandas.tests.series.common import TestData
+import pandas.util.testing as tm
+
 from pandas.tseries.offsets import (
-    BDay, CDay, DateOffset, MonthEnd, generate_range, prefix_mapping
-)
+    BDay, CDay, DateOffset, MonthEnd, generate_range, prefix_mapping)
 
 START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
 
diff --git a/pandas/tests/indexes/datetimes/test_datetime.py b/pandas/tests/indexes/datetimes/test_datetime.py
index 84214b331e8af2..cea56bf8030835 100644
--- a/pandas/tests/indexes/datetimes/test_datetime.py
+++ b/pandas/tests/indexes/datetimes/test_datetime.py
@@ -1,16 +1,16 @@
-import sys
 from datetime import date
+import sys
 
 import dateutil
 import numpy as np
 import pytest
 
+from pandas.compat import lrange
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
-    DataFrame, DatetimeIndex, Index, Timestamp, date_range, offsets
-)
-from pandas.compat import lrange
+    DataFrame, DatetimeIndex, Index, Timestamp, date_range, offsets)
+import pandas.util.testing as tm
 from pandas.util.testing import assert_almost_equal
 
 randn = np.random.randn
diff --git a/pandas/tests/indexes/datetimes/test_formats.py b/pandas/tests/indexes/datetimes/test_formats.py
index 4279c582e97770..d8e4104919e554 100644
--- a/pandas/tests/indexes/datetimes/test_formats.py
+++ b/pandas/tests/indexes/datetimes/test_formats.py
@@ -6,8 +6,8 @@
 import pytz
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DatetimeIndex, Series
+import pandas.util.testing as tm
 
 
 def test_to_native_types():
diff --git a/pandas/tests/indexes/datetimes/test_indexing.py b/pandas/tests/indexes/datetimes/test_indexing.py
index cb2b0dfe5d11c8..b66475612fe408 100644
--- a/pandas/tests/indexes/datetimes/test_indexing.py
+++ b/pandas/tests/indexes/datetimes/test_indexing.py
@@ -4,10 +4,12 @@
 import pytest
 import pytz
 
-import pandas as pd
 import pandas.compat as compat
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import DatetimeIndex, Index, Timestamp, date_range, notna
+import pandas.util.testing as tm
+
 from pandas.tseries.offsets import BDay, CDay
 
 START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
diff --git a/pandas/tests/indexes/datetimes/test_misc.py b/pandas/tests/indexes/datetimes/test_misc.py
index 00d816459626bb..6d6f13bb763f69 100644
--- a/pandas/tests/indexes/datetimes/test_misc.py
+++ b/pandas/tests/indexes/datetimes/test_misc.py
@@ -6,10 +6,9 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
-    DatetimeIndex, Index, Timestamp, compat, date_range, datetime, offsets
-)
+    DatetimeIndex, Index, Timestamp, compat, date_range, datetime, offsets)
+import pandas.util.testing as tm
 
 
 class TestTimeSeries(object):
diff --git a/pandas/tests/indexes/datetimes/test_ops.py b/pandas/tests/indexes/datetimes/test_ops.py
index 086c687148292b..2cb7482cda617d 100644
--- a/pandas/tests/indexes/datetimes/test_ops.py
+++ b/pandas/tests/indexes/datetimes/test_ops.py
@@ -1,17 +1,18 @@
-import warnings
 from datetime import datetime
+import warnings
 
 import numpy as np
 import pytest
 
+from pandas.core.dtypes.generic import ABCDateOffset
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
     DatetimeIndex, Index, PeriodIndex, Series, Timestamp, bdate_range,
-    date_range
-)
-from pandas.core.dtypes.generic import ABCDateOffset
+    date_range)
 from pandas.tests.test_base import Ops
+import pandas.util.testing as tm
+
 from pandas.tseries.offsets import BDay, BMonthEnd, CDay, Day, Hour
 
 START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
diff --git a/pandas/tests/indexes/datetimes/test_partial_slicing.py b/pandas/tests/indexes/datetimes/test_partial_slicing.py
index ae50ccedd79176..27e53c15238bed 100644
--- a/pandas/tests/indexes/datetimes/test_partial_slicing.py
+++ b/pandas/tests/indexes/datetimes/test_partial_slicing.py
@@ -1,15 +1,14 @@
 """ test partial slicing on Series/Frame """
 
-import operator as op
 from datetime import datetime
+import operator as op
 
 import numpy as np
 import pytest
 
 import pandas as pd
 from pandas import (
-    DataFrame, DatetimeIndex, Index, Series, Timedelta, Timestamp, date_range
-)
+    DataFrame, DatetimeIndex, Index, Series, Timedelta, Timestamp, date_range)
 from pandas.core.indexing import IndexingError
 from pandas.util import testing as tm
 
diff --git a/pandas/tests/indexes/datetimes/test_scalar_compat.py b/pandas/tests/indexes/datetimes/test_scalar_compat.py
index dac2df520c8e4d..b644cb5844d9b8 100644
--- a/pandas/tests/indexes/datetimes/test_scalar_compat.py
+++ b/pandas/tests/indexes/datetimes/test_scalar_compat.py
@@ -8,8 +8,9 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DatetimeIndex, Timestamp, date_range
+import pandas.util.testing as tm
+
 from pandas.tseries.frequencies import to_offset
 
 
diff --git a/pandas/tests/indexes/datetimes/test_setops.py b/pandas/tests/indexes/datetimes/test_setops.py
index 896d1cfd0094c1..d72bf275463ac2 100644
--- a/pandas/tests/indexes/datetimes/test_setops.py
+++ b/pandas/tests/indexes/datetimes/test_setops.py
@@ -3,13 +3,14 @@
 import numpy as np
 import pytest
 
-import pandas as pd
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import (
     DataFrame, DatetimeIndex, Index, Int64Index, Series, bdate_range,
-    date_range, to_datetime
-)
+    date_range, to_datetime)
+import pandas.util.testing as tm
+
 from pandas.tseries.offsets import BMonthEnd, Minute, MonthEnd
 
 START, END = datetime(2009, 1, 1), datetime(2010, 1, 1)
diff --git a/pandas/tests/indexes/datetimes/test_timezones.py b/pandas/tests/indexes/datetimes/test_timezones.py
index 6309206f48b1a2..9ad540b1744384 100644
--- a/pandas/tests/indexes/datetimes/test_timezones.py
+++ b/pandas/tests/indexes/datetimes/test_timezones.py
@@ -6,20 +6,20 @@
 from distutils.version import LooseVersion
 
 import dateutil
+from dateutil.tz import gettz, tzlocal
 import numpy as np
 import pytest
 import pytz
-from dateutil.tz import gettz, tzlocal
 
-import pandas as pd
+from pandas._libs.tslibs import conversion, timezones
+from pandas.compat import PY3, lrange, zip
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import (
     DatetimeIndex, Index, Timestamp, bdate_range, date_range, isna,
-    to_datetime
-)
-from pandas._libs.tslibs import conversion, timezones
-from pandas.compat import PY3, lrange, zip
+    to_datetime)
+import pandas.util.testing as tm
 
 
 class FixedOffset(tzinfo):
diff --git a/pandas/tests/indexes/datetimes/test_tools.py b/pandas/tests/indexes/datetimes/test_tools.py
index 428888a0e366d6..ba18f9b34574d3 100644
--- a/pandas/tests/indexes/datetimes/test_tools.py
+++ b/pandas/tests/indexes/datetimes/test_tools.py
@@ -1,29 +1,30 @@
 """ test to_datetime """
 
 import calendar
-import locale
 from datetime import datetime, time
 from distutils.version import LooseVersion
+import locale
 
 import dateutil
+from dateutil.parser import parse
+from dateutil.tz.tz import tzoffset
 import numpy as np
 import pytest
 import pytz
-from dateutil.parser import parse
-from dateutil.tz.tz import tzoffset
 
-import pandas as pd
-import pandas.util._test_decorators as td
-from pandas import (
-    DataFrame, DatetimeIndex, Index, NaT, Series, Timestamp, compat,
-    date_range, isna, to_datetime
-)
 from pandas._libs import tslib
 from pandas._libs.tslibs import parsing
 from pandas.compat import PY3, lmap
+from pandas.errors import OutOfBoundsDatetime
+import pandas.util._test_decorators as td
+
 from pandas.core.dtypes.common import is_datetime64_ns_dtype
+
+import pandas as pd
+from pandas import (
+    DataFrame, DatetimeIndex, Index, NaT, Series, Timestamp, compat,
+    date_range, isna, to_datetime)
 from pandas.core.tools import datetimes as tools
-from pandas.errors import OutOfBoundsDatetime
 from pandas.util import testing as tm
 from pandas.util.testing import assert_series_equal
 
diff --git a/pandas/tests/indexes/multi/test_compat.py b/pandas/tests/indexes/multi/test_compat.py
index ef3f7ddbbf81dc..f05b53522fa31a 100644
--- a/pandas/tests/indexes/multi/test_compat.py
+++ b/pandas/tests/indexes/multi/test_compat.py
@@ -4,10 +4,11 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
-from pandas import MultiIndex
 from pandas.compat import PY3, long
 
+from pandas import MultiIndex
+import pandas.util.testing as tm
+
 
 def test_numeric_compat(idx):
     tm.assert_raises_regex(TypeError, "cannot perform __mul__",
diff --git a/pandas/tests/indexes/multi/test_constructor.py b/pandas/tests/indexes/multi/test_constructor.py
index ca9b2766f37981..833de283e5367b 100644
--- a/pandas/tests/indexes/multi/test_constructor.py
+++ b/pandas/tests/indexes/multi/test_constructor.py
@@ -5,13 +5,15 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import Index, MultiIndex, date_range
 from pandas._libs.tslib import Timestamp
 from pandas.compat import lrange, range
+
 from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
 
+import pandas as pd
+from pandas import Index, MultiIndex, date_range
+import pandas.util.testing as tm
+
 
 def test_constructor_single_level():
     result = MultiIndex(levels=[['foo', 'bar', 'baz', 'qux']],
diff --git a/pandas/tests/indexes/multi/test_contains.py b/pandas/tests/indexes/multi/test_contains.py
index c846af3e7cfbe3..deff6aacf8f9cf 100644
--- a/pandas/tests/indexes/multi/test_contains.py
+++ b/pandas/tests/indexes/multi/test_contains.py
@@ -3,10 +3,11 @@
 import numpy as np
 import pytest
 
+from pandas.compat import PYPY
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import MultiIndex
-from pandas.compat import PYPY
+import pandas.util.testing as tm
 
 
 def test_contains_top_level():
diff --git a/pandas/tests/indexes/multi/test_copy.py b/pandas/tests/indexes/multi/test_copy.py
index 99a5bcc1c217bb..0d09e3ef2e4b1c 100644
--- a/pandas/tests/indexes/multi/test_copy.py
+++ b/pandas/tests/indexes/multi/test_copy.py
@@ -4,8 +4,8 @@
 
 import pytest
 
-import pandas.util.testing as tm
 from pandas import MultiIndex
+import pandas.util.testing as tm
 
 
 def assert_multiindex_copied(copy, original):
diff --git a/pandas/tests/indexes/multi/test_equivalence.py b/pandas/tests/indexes/multi/test_equivalence.py
index e3af327ededa2f..41cb2409f05329 100644
--- a/pandas/tests/indexes/multi/test_equivalence.py
+++ b/pandas/tests/indexes/multi/test_equivalence.py
@@ -3,10 +3,11 @@
 
 import numpy as np
 
+from pandas.compat import lrange, lzip, range
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import Index, MultiIndex, Series
-from pandas.compat import lrange, lzip, range
+import pandas.util.testing as tm
 
 
 def test_equals(idx):
diff --git a/pandas/tests/indexes/multi/test_get_set.py b/pandas/tests/indexes/multi/test_get_set.py
index cac32ce7040b44..e72b76ed072694 100644
--- a/pandas/tests/indexes/multi/test_get_set.py
+++ b/pandas/tests/indexes/multi/test_get_set.py
@@ -4,10 +4,11 @@
 import numpy as np
 import pytest
 
+from pandas.compat import range
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import CategoricalIndex, Index, MultiIndex
-from pandas.compat import range
+import pandas.util.testing as tm
 
 
 def assert_matching(actual, expected, check_dtype=False):
diff --git a/pandas/tests/indexes/multi/test_indexing.py b/pandas/tests/indexes/multi/test_indexing.py
index ec83ae4766ab05..2b5f16b0ea0c81 100644
--- a/pandas/tests/indexes/multi/test_indexing.py
+++ b/pandas/tests/indexes/multi/test_indexing.py
@@ -6,14 +6,14 @@
 import numpy as np
 import pytest
 
+from pandas.compat import lrange
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
     Categorical, CategoricalIndex, Index, IntervalIndex, MultiIndex,
-    date_range
-)
-from pandas.compat import lrange
+    date_range)
 from pandas.core.indexes.base import InvalidIndexError
+import pandas.util.testing as tm
 from pandas.util.testing import assert_almost_equal
 
 
diff --git a/pandas/tests/indexes/multi/test_sorting.py b/pandas/tests/indexes/multi/test_sorting.py
index b2f12405eb195c..80e2b811ac062d 100644
--- a/pandas/tests/indexes/multi/test_sorting.py
+++ b/pandas/tests/indexes/multi/test_sorting.py
@@ -2,12 +2,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import CategoricalIndex, DataFrame, Index, MultiIndex, RangeIndex
 from pandas.compat import lrange
 from pandas.errors import PerformanceWarning, UnsortedIndexError
 
+import pandas as pd
+from pandas import CategoricalIndex, DataFrame, Index, MultiIndex, RangeIndex
+import pandas.util.testing as tm
+
 
 def test_sortlevel(idx):
     import random
diff --git a/pandas/tests/indexes/period/test_arithmetic.py b/pandas/tests/indexes/period/test_arithmetic.py
index 5864bc0cefcbc3..2c04f22f8b450c 100644
--- a/pandas/tests/indexes/period/test_arithmetic.py
+++ b/pandas/tests/indexes/period/test_arithmetic.py
@@ -4,8 +4,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import PeriodIndex
+import pandas.util.testing as tm
 
 
 class TestPeriodIndexArithmetic(object):
diff --git a/pandas/tests/indexes/period/test_astype.py b/pandas/tests/indexes/period/test_astype.py
index f254cf2a9cae8f..f7c2bf3d6bf4f0 100644
--- a/pandas/tests/indexes/period/test_astype.py
+++ b/pandas/tests/indexes/period/test_astype.py
@@ -4,8 +4,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import Index, Int64Index, NaT, Period, PeriodIndex, period_range
+import pandas.util.testing as tm
 
 
 class TestPeriodIndexAsType(object):
diff --git a/pandas/tests/indexes/period/test_construction.py b/pandas/tests/indexes/period/test_construction.py
index cfc6c3b8b0a2e9..9622f47697f8df 100644
--- a/pandas/tests/indexes/period/test_construction.py
+++ b/pandas/tests/indexes/period/test_construction.py
@@ -1,14 +1,15 @@
 import numpy as np
 import pytest
 
+from pandas.compat import PY3, lmap, lrange, text_type
+
+from pandas.core.dtypes.dtypes import PeriodDtype
+
 import pandas as pd
+from pandas import (
+    Index, Period, PeriodIndex, Series, date_range, offsets, period_range)
 import pandas.core.indexes.period as period
 import pandas.util.testing as tm
-from pandas import (
-    Index, Period, PeriodIndex, Series, date_range, offsets, period_range
-)
-from pandas.compat import PY3, lmap, lrange, text_type
-from pandas.core.dtypes.dtypes import PeriodDtype
 
 
 class TestPeriodIndex(object):
diff --git a/pandas/tests/indexes/period/test_formats.py b/pandas/tests/indexes/period/test_formats.py
index 87211d091e4eac..d4035efa2b866c 100644
--- a/pandas/tests/indexes/period/test_formats.py
+++ b/pandas/tests/indexes/period/test_formats.py
@@ -2,8 +2,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import PeriodIndex
+import pandas.util.testing as tm
 
 
 def test_to_native_types():
diff --git a/pandas/tests/indexes/period/test_indexing.py b/pandas/tests/indexes/period/test_indexing.py
index b720f56eeab939..fafba144bb1484 100644
--- a/pandas/tests/indexes/period/test_indexing.py
+++ b/pandas/tests/indexes/period/test_indexing.py
@@ -3,13 +3,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-from pandas import (
-    DatetimeIndex, Period, PeriodIndex, Series, notna, period_range
-)
 from pandas._libs import tslibs
 from pandas._libs.tslibs import period as libperiod
 from pandas.compat import lrange
+
+import pandas as pd
+from pandas import (
+    DatetimeIndex, Period, PeriodIndex, Series, notna, period_range)
 from pandas.util import testing as tm
 
 
diff --git a/pandas/tests/indexes/period/test_ops.py b/pandas/tests/indexes/period/test_ops.py
index 80550292ed4f8f..516eb8971abafc 100644
--- a/pandas/tests/indexes/period/test_ops.py
+++ b/pandas/tests/indexes/period/test_ops.py
@@ -2,12 +2,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
 import pandas._libs.tslib as tslib
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import DatetimeIndex, Index, Period, PeriodIndex, Series
 from pandas.core.arrays import PeriodArray
 from pandas.tests.test_base import Ops
+import pandas.util.testing as tm
 
 
 class TestPeriodIndexOps(Ops):
diff --git a/pandas/tests/indexes/period/test_partial_slicing.py b/pandas/tests/indexes/period/test_partial_slicing.py
index eec761395d971c..fcf1156266880f 100644
--- a/pandas/tests/indexes/period/test_partial_slicing.py
+++ b/pandas/tests/indexes/period/test_partial_slicing.py
@@ -3,8 +3,7 @@
 
 import pandas as pd
 from pandas import (
-    DataFrame, DatetimeIndex, Period, PeriodIndex, Series, period_range
-)
+    DataFrame, DatetimeIndex, Period, PeriodIndex, Series, period_range)
 from pandas.util import testing as tm
 
 
diff --git a/pandas/tests/indexes/period/test_period.py b/pandas/tests/indexes/period/test_period.py
index 300d5ef609b3ef..8b2e91450c8c0d 100644
--- a/pandas/tests/indexes/period/test_period.py
+++ b/pandas/tests/indexes/period/test_period.py
@@ -1,12 +1,12 @@
 import numpy as np
 import pytest
 
-import pandas as pd
 import pandas.util._test_decorators as td
+
+import pandas as pd
 from pandas import (
     DataFrame, DatetimeIndex, Index, NaT, Period, PeriodIndex, Series,
-    date_range, offsets, period_range
-)
+    date_range, offsets, period_range)
 from pandas.util import testing as tm
 
 from ..datetimelike import DatetimeLike
diff --git a/pandas/tests/indexes/period/test_period_range.py b/pandas/tests/indexes/period/test_period_range.py
index fd8d2f94c17991..11d38df1dd49cd 100644
--- a/pandas/tests/indexes/period/test_period_range.py
+++ b/pandas/tests/indexes/period/test_period_range.py
@@ -1,7 +1,7 @@
 import pytest
 
-import pandas.util.testing as tm
 from pandas import NaT, Period, PeriodIndex, date_range, period_range
+import pandas.util.testing as tm
 
 
 class TestPeriodRange(object):
diff --git a/pandas/tests/indexes/period/test_scalar_compat.py b/pandas/tests/indexes/period/test_scalar_compat.py
index 48c1d5b8dd7063..01fb1e3dc7e022 100644
--- a/pandas/tests/indexes/period/test_scalar_compat.py
+++ b/pandas/tests/indexes/period/test_scalar_compat.py
@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
 """Tests for PeriodIndex behaving like a vectorized Period scalar"""
 
-import pandas.util.testing as tm
 from pandas import PeriodIndex, Timedelta, date_range
+import pandas.util.testing as tm
 
 
 class TestPeriodIndexOps(object):
diff --git a/pandas/tests/indexes/period/test_setops.py b/pandas/tests/indexes/period/test_setops.py
index 479104fedcf745..c4dd23b1708db6 100644
--- a/pandas/tests/indexes/period/test_setops.py
+++ b/pandas/tests/indexes/period/test_setops.py
@@ -2,9 +2,9 @@
 import pytest
 
 import pandas as pd
+from pandas import Index, PeriodIndex, date_range, period_range
 import pandas.core.indexes.period as period
 import pandas.util.testing as tm
-from pandas import Index, PeriodIndex, date_range, period_range
 
 
 def _permute(obj):
diff --git a/pandas/tests/indexes/period/test_tools.py b/pandas/tests/indexes/period/test_tools.py
index 2919b97da58254..8d09273bde63de 100644
--- a/pandas/tests/indexes/period/test_tools.py
+++ b/pandas/tests/indexes/period/test_tools.py
@@ -3,15 +3,15 @@
 import numpy as np
 import pytest
 
+from pandas._libs.tslibs.ccalendar import MONTHS
+from pandas.compat import lrange
+
 import pandas as pd
-import pandas.core.indexes.period as period
-import pandas.util.testing as tm
 from pandas import (
     DatetimeIndex, Period, PeriodIndex, Series, Timedelta, Timestamp,
-    date_range, period_range, to_datetime
-)
-from pandas._libs.tslibs.ccalendar import MONTHS
-from pandas.compat import lrange
+    date_range, period_range, to_datetime)
+import pandas.core.indexes.period as period
+import pandas.util.testing as tm
 
 
 class TestPeriodRepresentation(object):
diff --git a/pandas/tests/indexes/test_numeric.py b/pandas/tests/indexes/test_numeric.py
index 6f151134bd24ff..8373cbc89149ac 100644
--- a/pandas/tests/indexes/test_numeric.py
+++ b/pandas/tests/indexes/test_numeric.py
@@ -5,12 +5,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import Float64Index, Index, Int64Index, Series, UInt64Index
 from pandas._libs.tslibs import Timestamp
 from pandas.compat import range
+
+import pandas as pd
+from pandas import Float64Index, Index, Int64Index, Series, UInt64Index
 from pandas.tests.indexes.common import Base
+import pandas.util.testing as tm
 
 
 class Numeric(Base):
diff --git a/pandas/tests/indexes/test_range.py b/pandas/tests/indexes/test_range.py
index 4bd66c070e731a..ecda48822eb0f5 100644
--- a/pandas/tests/indexes/test_range.py
+++ b/pandas/tests/indexes/test_range.py
@@ -1,16 +1,17 @@
 # -*- coding: utf-8 -*-
 
-import operator
 from datetime import datetime
 from itertools import combinations
+import operator
 
 import numpy as np
 import pytest
 
+from pandas.compat import PY3, range, u
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import Float64Index, Index, Int64Index, RangeIndex, Series, isna
-from pandas.compat import PY3, range, u
+import pandas.util.testing as tm
 
 from .test_numeric import Numeric
 
diff --git a/pandas/tests/indexing/common.py b/pandas/tests/indexing/common.py
index 1fd9bf86ff6ee1..5053c7f3d9875b 100644
--- a/pandas/tests/indexing/common.py
+++ b/pandas/tests/indexing/common.py
@@ -6,15 +6,17 @@
 import numpy as np
 import pytest
 
-from pandas import (
-    DataFrame, Float64Index, MultiIndex, Panel, Series, UInt64Index,
-    date_range
-)
 from pandas.compat import lrange
+
 from pandas.core.dtypes.common import is_scalar
-from pandas.io.formats.printing import pprint_thing
+
+from pandas import (
+    DataFrame, Float64Index, MultiIndex, Panel, Series, UInt64Index,
+    date_range)
 from pandas.util import testing as tm
 
+from pandas.io.formats.printing import pprint_thing
+
 _verbose = False
 
 
diff --git a/pandas/tests/indexing/interval/test_interval.py b/pandas/tests/indexing/interval/test_interval.py
index 67fa31637fc257..938caec006f3a0 100644
--- a/pandas/tests/indexing/interval/test_interval.py
+++ b/pandas/tests/indexing/interval/test_interval.py
@@ -2,8 +2,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DataFrame, Interval, IntervalIndex, Series
+import pandas.util.testing as tm
 
 
 class TestIntervalIndex(object):
diff --git a/pandas/tests/indexing/interval/test_interval_new.py b/pandas/tests/indexing/interval/test_interval_new.py
index 080f2abdad7dee..4b2ec0c4d17bf9 100644
--- a/pandas/tests/indexing/interval/test_interval_new.py
+++ b/pandas/tests/indexing/interval/test_interval_new.py
@@ -1,8 +1,8 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Interval, IntervalIndex, Series
+import pandas.util.testing as tm
 
 pytestmark = pytest.mark.skip(reason="new indexing tests for issue 16316")
 
diff --git a/pandas/tests/indexing/test_categorical.py b/pandas/tests/indexing/test_categorical.py
index 85f95e79cc003f..3a235e1eeb0dc9 100644
--- a/pandas/tests/indexing/test_categorical.py
+++ b/pandas/tests/indexing/test_categorical.py
@@ -3,15 +3,16 @@
 import numpy as np
 import pytest
 
-import pandas as pd
 import pandas.compat as compat
+
+from pandas.core.dtypes.common import is_categorical_dtype
+from pandas.core.dtypes.dtypes import CategoricalDtype
+
+import pandas as pd
 from pandas import (
     Categorical, CategoricalIndex, DataFrame, Index, Interval, Series,
-    Timestamp
-)
+    Timestamp)
 from pandas.api.types import CategoricalDtype as CDT
-from pandas.core.dtypes.common import is_categorical_dtype
-from pandas.core.dtypes.dtypes import CategoricalDtype
 from pandas.util import testing as tm
 from pandas.util.testing import assert_frame_equal, assert_series_equal
 
diff --git a/pandas/tests/indexing/test_chaining_and_caching.py b/pandas/tests/indexing/test_chaining_and_caching.py
index 3762585558082c..71fec75f9a7d3a 100644
--- a/pandas/tests/indexing/test_chaining_and_caching.py
+++ b/pandas/tests/indexing/test_chaining_and_caching.py
@@ -4,8 +4,7 @@
 import pandas as pd
 from pandas import (
     DataFrame, MultiIndex, Series, Timestamp, compat, date_range,
-    option_context
-)
+    option_context)
 from pandas.core import common as com
 from pandas.util import testing as tm
 
diff --git a/pandas/tests/indexing/test_coercion.py b/pandas/tests/indexing/test_coercion.py
index 643b6081d176a2..65110d49552944 100644
--- a/pandas/tests/indexing/test_coercion.py
+++ b/pandas/tests/indexing/test_coercion.py
@@ -5,8 +5,9 @@
 import numpy as np
 import pytest
 
-import pandas as pd
 import pandas.compat as compat
+
+import pandas as pd
 import pandas.util.testing as tm
 
 ###############################################################
diff --git a/pandas/tests/indexing/test_datetime.py b/pandas/tests/indexing/test_datetime.py
index 5fd1724f6e95c1..11fb90ebd9bb9b 100644
--- a/pandas/tests/indexing/test_datetime.py
+++ b/pandas/tests/indexing/test_datetime.py
@@ -1,7 +1,7 @@
 from datetime import datetime, timedelta
 
-import numpy as np
 from dateutil import tz
+import numpy as np
 
 import pandas as pd
 from pandas import DataFrame, Index, Series, Timestamp, date_range
diff --git a/pandas/tests/indexing/test_floats.py b/pandas/tests/indexing/test_floats.py
index c7fe9959b048a4..0a55b3f67dd3f8 100644
--- a/pandas/tests/indexing/test_floats.py
+++ b/pandas/tests/indexing/test_floats.py
@@ -5,10 +5,9 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
 from pandas import (
-    DataFrame, Float64Index, Index, Int64Index, RangeIndex, Series
-)
+    DataFrame, Float64Index, Index, Int64Index, RangeIndex, Series)
+import pandas.util.testing as tm
 from pandas.util.testing import assert_almost_equal, assert_series_equal
 
 ignore_ix = pytest.mark.filterwarnings("ignore:\\n.ix:DeprecationWarning")
diff --git a/pandas/tests/indexing/test_iloc.py b/pandas/tests/indexing/test_iloc.py
index e2b6a37096493f..6d0b516d8ebf00 100644
--- a/pandas/tests/indexing/test_iloc.py
+++ b/pandas/tests/indexing/test_iloc.py
@@ -5,10 +5,11 @@
 import numpy as np
 import pytest
 
+from pandas.compat import lmap, lrange
+
 import pandas as pd
 from pandas import DataFrame, Series, concat, date_range, isna
 from pandas.api.types import is_scalar
-from pandas.compat import lmap, lrange
 from pandas.tests.indexing.common import Base
 from pandas.util import testing as tm
 
diff --git a/pandas/tests/indexing/test_indexing.py b/pandas/tests/indexing/test_indexing.py
index e96e249743468a..3b95ba8e4b9d87 100644
--- a/pandas/tests/indexing/test_indexing.py
+++ b/pandas/tests/indexing/test_indexing.py
@@ -3,22 +3,23 @@
 
 """ test fancy indexing & misc """
 
-import weakref
 from datetime import datetime
 from warnings import catch_warnings, simplefilter
+import weakref
 
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, MultiIndex, NaT, Series
 from pandas.compat import PY2, StringIO, lrange, lzip, range
+
 from pandas.core.dtypes.common import is_float_dtype, is_integer_dtype
+
+import pandas as pd
+from pandas import DataFrame, Index, MultiIndex, NaT, Series
 from pandas.core.indexing import (
-    _maybe_numeric_slice, _non_reducing_slice, validate_indices
-)
+    _maybe_numeric_slice, _non_reducing_slice, validate_indices)
 from pandas.tests.indexing.common import Base, _mklbl
+import pandas.util.testing as tm
 
 # ------------------------------------------------------------------------
 # Indexing test cases
diff --git a/pandas/tests/indexing/test_indexing_engines.py b/pandas/tests/indexing/test_indexing_engines.py
index 410eba99948ce1..dcdfbcb7fbea2d 100644
--- a/pandas/tests/indexing/test_indexing_engines.py
+++ b/pandas/tests/indexing/test_indexing_engines.py
@@ -1,9 +1,10 @@
 import numpy as np
 
-import pandas.util.testing as tm
-from pandas import compat
 from pandas._libs import algos as libalgos, index as libindex
 
+from pandas import compat
+import pandas.util.testing as tm
+
 
 class TestNumericEngine(object):
     def test_is_monotonic(self, numeric_indexing_engine_type_and_dtype):
diff --git a/pandas/tests/indexing/test_indexing_slow.py b/pandas/tests/indexing/test_indexing_slow.py
index 9715fc2bb5946b..5fd1431ac210c8 100644
--- a/pandas/tests/indexing/test_indexing_slow.py
+++ b/pandas/tests/indexing/test_indexing_slow.py
@@ -6,8 +6,8 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas.core.api import DataFrame, MultiIndex, Series
+import pandas.util.testing as tm
 
 
 class TestIndexingSlow(object):
diff --git a/pandas/tests/indexing/test_ix.py b/pandas/tests/indexing/test_ix.py
index 0e99be31f6b933..850f80241a4776 100644
--- a/pandas/tests/indexing/test_ix.py
+++ b/pandas/tests/indexing/test_ix.py
@@ -5,11 +5,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-from pandas import DataFrame, MultiIndex, Series, option_context
 from pandas.compat import lrange
-from pandas.core.dtypes.common import is_scalar
 from pandas.errors import PerformanceWarning
+
+from pandas.core.dtypes.common import is_scalar
+
+import pandas as pd
+from pandas import DataFrame, MultiIndex, Series, option_context
 from pandas.util import testing as tm
 
 
diff --git a/pandas/tests/indexing/test_loc.py b/pandas/tests/indexing/test_loc.py
index 9314c2bcc84158..df0180c7a5bf74 100644
--- a/pandas/tests/indexing/test_loc.py
+++ b/pandas/tests/indexing/test_loc.py
@@ -6,10 +6,11 @@
 import numpy as np
 import pytest
 
+from pandas.compat import PY2, StringIO, lrange
+
 import pandas as pd
 from pandas import DataFrame, Index, MultiIndex, Series, Timestamp, date_range
 from pandas.api.types import is_scalar
-from pandas.compat import PY2, StringIO, lrange
 from pandas.tests.indexing.common import Base
 from pandas.util import testing as tm
 
diff --git a/pandas/tests/indexing/test_multiindex.py b/pandas/tests/indexing/test_multiindex.py
index 42d7b35a0a2fdb..dcf148f199d52c 100644
--- a/pandas/tests/indexing/test_multiindex.py
+++ b/pandas/tests/indexing/test_multiindex.py
@@ -3,11 +3,11 @@
 import numpy as np
 import pytest
 
+from pandas.errors import PerformanceWarning, UnsortedIndexError
+
 import pandas as pd
 from pandas import (
-    DataFrame, Index, MultiIndex, Panel, Series, Timestamp, date_range
-)
-from pandas.errors import PerformanceWarning, UnsortedIndexError
+    DataFrame, Index, MultiIndex, Panel, Series, Timestamp, date_range)
 from pandas.tests.indexing.common import _mklbl
 from pandas.util import testing as tm
 
diff --git a/pandas/tests/io/parser/c_parser_only.py b/pandas/tests/io/parser/c_parser_only.py
index 7769b62dc02066..edcfe1c0768cd3 100644
--- a/pandas/tests/io/parser/c_parser_only.py
+++ b/pandas/tests/io/parser/c_parser_only.py
@@ -14,11 +14,12 @@
 import numpy as np
 import pytest
 
-import pandas as pd
+from pandas.compat import StringIO, lrange, range
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import DataFrame
-from pandas.compat import StringIO, lrange, range
+import pandas.util.testing as tm
 
 
 class CParserTests(object):
diff --git a/pandas/tests/io/parser/comment.py b/pandas/tests/io/parser/comment.py
index c71f92d8fb1be1..fc2310ca1daaf3 100644
--- a/pandas/tests/io/parser/comment.py
+++ b/pandas/tests/io/parser/comment.py
@@ -7,10 +7,11 @@
 
 import numpy as np
 
-import pandas.util.testing as tm
-from pandas import DataFrame
 from pandas.compat import StringIO
 
+from pandas import DataFrame
+import pandas.util.testing as tm
+
 
 class CommentTests(object):
 
diff --git a/pandas/tests/io/parser/common.py b/pandas/tests/io/parser/common.py
index 82557815ed5cfd..da8118ef3e1234 100644
--- a/pandas/tests/io/parser/common.py
+++ b/pandas/tests/io/parser/common.py
@@ -1,24 +1,26 @@
 # -*- coding: utf-8 -*-
 
 import codecs
+from collections import OrderedDict
 import csv
+from datetime import datetime
+from io import TextIOWrapper
 import os
 import platform
 import re
 import sys
-from collections import OrderedDict
-from datetime import datetime
-from io import TextIOWrapper
 
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, MultiIndex, Series, compat
 from pandas._libs.tslib import Timestamp
 from pandas.compat import PY3, BytesIO, StringIO, lrange, range, u
 from pandas.errors import DtypeWarning, EmptyDataError, ParserError
+
+import pandas as pd
+from pandas import DataFrame, Index, MultiIndex, Series, compat
+import pandas.util.testing as tm
+
 from pandas.io.common import URLError
 from pandas.io.parsers import TextFileReader, TextParser
 
diff --git a/pandas/tests/io/parser/compression.py b/pandas/tests/io/parser/compression.py
index 5efed89663e0fe..2d32e383c7fee6 100644
--- a/pandas/tests/io/parser/compression.py
+++ b/pandas/tests/io/parser/compression.py
@@ -10,9 +10,10 @@
 
 import pytest
 
-import pandas as pd
 import pandas.compat as compat
 import pandas.util._test_decorators as td
+
+import pandas as pd
 import pandas.util.testing as tm
 
 try:
diff --git a/pandas/tests/io/parser/converters.py b/pandas/tests/io/parser/converters.py
index be14e7be0ab9b3..f17ad019469aba 100644
--- a/pandas/tests/io/parser/converters.py
+++ b/pandas/tests/io/parser/converters.py
@@ -10,12 +10,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import DataFrame, Index
 from pandas._libs.tslib import Timestamp
 from pandas.compat import StringIO, lmap, parse_date
 
+import pandas as pd
+from pandas import DataFrame, Index
+import pandas.util.testing as tm
+
 
 class ConverterTests(object):
 
diff --git a/pandas/tests/io/parser/dialect.py b/pandas/tests/io/parser/dialect.py
index 2a519a0083f407..480ce9ef361d09 100644
--- a/pandas/tests/io/parser/dialect.py
+++ b/pandas/tests/io/parser/dialect.py
@@ -7,11 +7,12 @@
 
 import csv
 
-import pandas.util.testing as tm
-from pandas import DataFrame
 from pandas.compat import StringIO
 from pandas.errors import ParserWarning
 
+from pandas import DataFrame
+import pandas.util.testing as tm
+
 
 class DialectTests(object):
 
diff --git a/pandas/tests/io/parser/dtypes.py b/pandas/tests/io/parser/dtypes.py
index 00dfb616c18cae..950795b33d4609 100644
--- a/pandas/tests/io/parser/dtypes.py
+++ b/pandas/tests/io/parser/dtypes.py
@@ -8,13 +8,15 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import Categorical, DataFrame, Index, MultiIndex, Series
 from pandas.compat import StringIO
-from pandas.core.dtypes.dtypes import CategoricalDtype
 from pandas.errors import ParserWarning
 
+from pandas.core.dtypes.dtypes import CategoricalDtype
+
+import pandas as pd
+from pandas import Categorical, DataFrame, Index, MultiIndex, Series
+import pandas.util.testing as tm
+
 
 class DtypeTests(object):
 
diff --git a/pandas/tests/io/parser/header.py b/pandas/tests/io/parser/header.py
index ced59fe1696d62..3a6db0fafa7c6f 100644
--- a/pandas/tests/io/parser/header.py
+++ b/pandas/tests/io/parser/header.py
@@ -10,10 +10,11 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, MultiIndex
 from pandas.compat import StringIO, lrange, u
 
+from pandas import DataFrame, Index, MultiIndex
+import pandas.util.testing as tm
+
 
 class HeaderTests(object):
 
diff --git a/pandas/tests/io/parser/index_col.py b/pandas/tests/io/parser/index_col.py
index 973fa4c57545a8..2909ef6214e621 100644
--- a/pandas/tests/io/parser/index_col.py
+++ b/pandas/tests/io/parser/index_col.py
@@ -8,10 +8,11 @@
 
 import pytest
 
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, MultiIndex
 from pandas.compat import StringIO
 
+from pandas import DataFrame, Index, MultiIndex
+import pandas.util.testing as tm
+
 
 class IndexColTests(object):
 
diff --git a/pandas/tests/io/parser/mangle_dupes.py b/pandas/tests/io/parser/mangle_dupes.py
index d043f644600281..1ebfa9cb0f6454 100644
--- a/pandas/tests/io/parser/mangle_dupes.py
+++ b/pandas/tests/io/parser/mangle_dupes.py
@@ -6,10 +6,11 @@
 de-duplicated (if mangling requested) or ignored otherwise.
 """
 
-import pandas.util.testing as tm
-from pandas import DataFrame
 from pandas.compat import StringIO
 
+from pandas import DataFrame
+import pandas.util.testing as tm
+
 
 class DupeColumnTests(object):
     def test_basic(self):
diff --git a/pandas/tests/io/parser/multithread.py b/pandas/tests/io/parser/multithread.py
index dee7067ea87286..0be3a429f5f649 100644
--- a/pandas/tests/io/parser/multithread.py
+++ b/pandas/tests/io/parser/multithread.py
@@ -11,10 +11,11 @@
 
 import numpy as np
 
+from pandas.compat import BytesIO, range
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DataFrame
-from pandas.compat import BytesIO, range
+import pandas.util.testing as tm
 
 
 def _construct_dataframe(num_rows):
diff --git a/pandas/tests/io/parser/na_values.py b/pandas/tests/io/parser/na_values.py
index 392f4de2ecaaf2..5e67b62879acbc 100644
--- a/pandas/tests/io/parser/na_values.py
+++ b/pandas/tests/io/parser/na_values.py
@@ -6,14 +6,16 @@
 """
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
-import pandas.io.common as com
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, MultiIndex
 from pandas.compat import StringIO, range
 
+from pandas import DataFrame, Index, MultiIndex
+import pandas.util.testing as tm
+
+import pandas.io.common as com
+
 
 class NAvaluesTests(object):
 
diff --git a/pandas/tests/io/parser/parse_dates.py b/pandas/tests/io/parser/parse_dates.py
index d893b91226976e..4c2c5b754f9bb0 100644
--- a/pandas/tests/io/parser/parse_dates.py
+++ b/pandas/tests/io/parser/parse_dates.py
@@ -12,16 +12,19 @@
 import pytest
 import pytz
 
-import pandas as pd
-import pandas.io.date_converters as conv
-import pandas.io.parsers as parsers
-import pandas.util.testing as tm
-from pandas import DataFrame, DatetimeIndex, Index, MultiIndex, Series, compat
 from pandas._libs.tslib import Timestamp
 from pandas._libs.tslibs import parsing
+import pandas.compat as compat
 from pandas.compat import StringIO, lrange, parse_date
 from pandas.compat.numpy import np_array_datetime64_compat
+
+import pandas as pd
+from pandas import DataFrame, DatetimeIndex, Index, MultiIndex, Series
 from pandas.core.indexes.datetimes import date_range
+import pandas.util.testing as tm
+
+import pandas.io.date_converters as conv
+import pandas.io.parsers as parsers
 
 
 class ParseDatesTests(object):
diff --git a/pandas/tests/io/parser/python_parser_only.py b/pandas/tests/io/parser/python_parser_only.py
index 5d2f6b7231a5d5..c3c87bca24a473 100644
--- a/pandas/tests/io/parser/python_parser_only.py
+++ b/pandas/tests/io/parser/python_parser_only.py
@@ -11,11 +11,13 @@
 
 import pytest
 
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, compat
+import pandas.compat as compat
 from pandas.compat import BytesIO, StringIO, u
 from pandas.errors import ParserError
 
+from pandas import DataFrame, Index
+import pandas.util.testing as tm
+
 
 class PythonParserTests(object):
 
diff --git a/pandas/tests/io/parser/quoting.py b/pandas/tests/io/parser/quoting.py
index 27ee824cd2556a..270a5430e6da40 100644
--- a/pandas/tests/io/parser/quoting.py
+++ b/pandas/tests/io/parser/quoting.py
@@ -7,11 +7,12 @@
 
 import csv
 
-import pandas.util.testing as tm
-from pandas import DataFrame
 from pandas.compat import PY3, StringIO, u
 from pandas.errors import ParserError
 
+from pandas import DataFrame
+import pandas.util.testing as tm
+
 
 class QuotingTests(object):
 
diff --git a/pandas/tests/io/parser/skiprows.py b/pandas/tests/io/parser/skiprows.py
index 89a7b5fd0ea1f1..5d1b3b207a2402 100644
--- a/pandas/tests/io/parser/skiprows.py
+++ b/pandas/tests/io/parser/skiprows.py
@@ -9,11 +9,12 @@
 
 import numpy as np
 
-import pandas.util.testing as tm
-from pandas import DataFrame
 from pandas.compat import StringIO, lrange, range
 from pandas.errors import EmptyDataError
 
+from pandas import DataFrame
+import pandas.util.testing as tm
+
 
 class SkipRowsTests(object):
 
diff --git a/pandas/tests/io/parser/test_network.py b/pandas/tests/io/parser/test_network.py
index 8b8bf3a339d85d..e54da94089cfdf 100644
--- a/pandas/tests/io/parser/test_network.py
+++ b/pandas/tests/io/parser/test_network.py
@@ -9,10 +9,12 @@
 import numpy as np
 import pytest
 
+from pandas.compat import BytesIO, StringIO
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
 from pandas import DataFrame
-from pandas.compat import BytesIO, StringIO
+import pandas.util.testing as tm
+
 from pandas.io.parsers import read_csv
 
 
diff --git a/pandas/tests/io/parser/test_parsers.py b/pandas/tests/io/parser/test_parsers.py
index 00879c096aa501..50d927176a7b47 100644
--- a/pandas/tests/io/parser/test_parsers.py
+++ b/pandas/tests/io/parser/test_parsers.py
@@ -4,12 +4,13 @@
 
 import pytest
 
-import pandas.core.common as com
-import pandas.util.testing as tm
-from pandas import DataFrame, read_csv, read_table
 from pandas._libs.tslib import Timestamp
 from pandas.compat import StringIO
 
+from pandas import DataFrame, read_csv, read_table
+import pandas.core.common as com
+import pandas.util.testing as tm
+
 from .c_parser_only import CParserTests
 from .comment import CommentTests
 from .common import ParserTests
diff --git a/pandas/tests/io/parser/test_read_fwf.py b/pandas/tests/io/parser/test_read_fwf.py
index 468640ae327bbf..f7846f7824ba50 100644
--- a/pandas/tests/io/parser/test_read_fwf.py
+++ b/pandas/tests/io/parser/test_read_fwf.py
@@ -11,10 +11,13 @@
 import numpy as np
 import pytest
 
+import pandas.compat as compat
+from pandas.compat import BytesIO, StringIO
+
 import pandas as pd
+from pandas import DataFrame
 import pandas.util.testing as tm
-from pandas import DataFrame, compat
-from pandas.compat import BytesIO, StringIO
+
 from pandas.io.parsers import EmptyDataError, read_csv, read_fwf
 
 
diff --git a/pandas/tests/io/parser/test_textreader.py b/pandas/tests/io/parser/test_textreader.py
index 94c69bbbb8d5f5..93c115ae0a57b3 100644
--- a/pandas/tests/io/parser/test_textreader.py
+++ b/pandas/tests/io/parser/test_textreader.py
@@ -9,17 +9,20 @@
 import sys
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
 import pandas._libs.parsers as parser
-import pandas.util.testing as tm
-from pandas import DataFrame, compat
 from pandas._libs.parsers import TextReader
+import pandas.compat as compat
 from pandas.compat import BytesIO, StringIO, map
-from pandas.io.parsers import TextFileReader, read_csv
+
+from pandas import DataFrame
+import pandas.util.testing as tm
 from pandas.util.testing import assert_frame_equal
 
+from pandas.io.parsers import TextFileReader, read_csv
+
 
 class TestTextReader(object):
 
diff --git a/pandas/tests/io/parser/test_unsupported.py b/pandas/tests/io/parser/test_unsupported.py
index c6fd2501167791..4437b0db9054e2 100644
--- a/pandas/tests/io/parser/test_unsupported.py
+++ b/pandas/tests/io/parser/test_unsupported.py
@@ -11,10 +11,12 @@
 
 import pytest
 
-import pandas.io.parsers as parsers
-import pandas.util.testing as tm
 from pandas.compat import StringIO
 from pandas.errors import ParserError
+
+import pandas.util.testing as tm
+
+import pandas.io.parsers as parsers
 from pandas.io.parsers import read_csv
 
 
diff --git a/pandas/tests/io/parser/usecols.py b/pandas/tests/io/parser/usecols.py
index 5fd2dc3f48e3ec..82d45b163d16a9 100644
--- a/pandas/tests/io/parser/usecols.py
+++ b/pandas/tests/io/parser/usecols.py
@@ -8,11 +8,12 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
-from pandas import DataFrame, Index
 from pandas._libs.tslib import Timestamp
 from pandas.compat import StringIO
 
+from pandas import DataFrame, Index
+import pandas.util.testing as tm
+
 
 class UsecolsTests(object):
     msg_validate_usecols_arg = ("'usecols' must either be list-like of all "
diff --git a/pandas/tests/io/test_stata.py b/pandas/tests/io/test_stata.py
index 7b9e23fca59aab..c6b6f6cab9ddd5 100644
--- a/pandas/tests/io/test_stata.py
+++ b/pandas/tests/io/test_stata.py
@@ -15,7 +15,7 @@
 
 import pandas as pd
 import pandas.util.testing as tm
-from pandas import compat
+import pandas.compat as compat
 from pandas.compat import iterkeys
 from pandas.core.dtypes.common import is_categorical_dtype
 from pandas.core.frame import DataFrame, Series
diff --git a/pandas/tests/scalar/interval/test_ops.py b/pandas/tests/scalar/interval/test_ops.py
index cfd9fc34faeff3..7eca24aa8af25a 100644
--- a/pandas/tests/scalar/interval/test_ops.py
+++ b/pandas/tests/scalar/interval/test_ops.py
@@ -1,8 +1,8 @@
 """Tests for Interval-Interval operations, such as overlaps, contains, etc."""
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Interval, Timedelta, Timestamp
+import pandas.util.testing as tm
 
 
 @pytest.fixture(params=[
diff --git a/pandas/tests/series/common.py b/pandas/tests/series/common.py
index ec7558e41ab40e..cacca38b2d6083 100644
--- a/pandas/tests/series/common.py
+++ b/pandas/tests/series/common.py
@@ -1,6 +1,7 @@
+from pandas.util._decorators import cache_readonly
+
 import pandas as pd
 import pandas.util.testing as tm
-from pandas.util._decorators import cache_readonly
 
 _ts = tm.makeTimeSeries()
 
diff --git a/pandas/tests/series/conftest.py b/pandas/tests/series/conftest.py
index 352e4df54fe5b3..431aacb1c8d568 100644
--- a/pandas/tests/series/conftest.py
+++ b/pandas/tests/series/conftest.py
@@ -1,7 +1,7 @@
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Series
+import pandas.util.testing as tm
 
 
 @pytest.fixture
diff --git a/pandas/tests/series/indexing/test_alter_index.py b/pandas/tests/series/indexing/test_alter_index.py
index ea6788a1a36ee1..25c930e8cade6c 100644
--- a/pandas/tests/series/indexing/test_alter_index.py
+++ b/pandas/tests/series/indexing/test_alter_index.py
@@ -4,13 +4,15 @@
 from datetime import datetime
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
+
+import pandas.compat as compat
+from pandas.compat import lrange, range
 
 import pandas as pd
+from pandas import Categorical, Series, date_range, isna
 import pandas.util.testing as tm
-from pandas import Categorical, Series, compat, date_range, isna
-from pandas.compat import lrange, range
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/indexing/test_boolean.py b/pandas/tests/series/indexing/test_boolean.py
index df92851f432278..5d1b81ba7dc1c9 100644
--- a/pandas/tests/series/indexing/test_boolean.py
+++ b/pandas/tests/series/indexing/test_boolean.py
@@ -4,15 +4,18 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import Index, Series, Timestamp, date_range, isna
 from pandas.compat import lrange, range
+
 from pandas.core.dtypes.common import is_integer
+
+import pandas as pd
+from pandas import Index, Series, Timestamp, date_range, isna
 from pandas.core.indexing import IndexingError
-from pandas.tseries.offsets import BDay
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
+from pandas.tseries.offsets import BDay
+
 
 def test_getitem_boolean(test_data):
     s = test_data.series
diff --git a/pandas/tests/series/indexing/test_datetime.py b/pandas/tests/series/indexing/test_datetime.py
index d63150165d7d35..a0da25c96caa6e 100644
--- a/pandas/tests/series/indexing/test_datetime.py
+++ b/pandas/tests/series/indexing/test_datetime.py
@@ -6,15 +6,15 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas._libs.index as _index
-import pandas.util.testing as tm
-from pandas import DataFrame, DatetimeIndex, NaT, Series, Timestamp, date_range
 from pandas._libs import tslib
+import pandas._libs.index as _index
 from pandas.compat import lrange, range
+
+import pandas as pd
+from pandas import DataFrame, DatetimeIndex, NaT, Series, Timestamp, date_range
+import pandas.util.testing as tm
 from pandas.util.testing import (
-    assert_almost_equal, assert_frame_equal, assert_series_equal
-)
+    assert_almost_equal, assert_frame_equal, assert_series_equal)
 
 
 """
diff --git a/pandas/tests/series/indexing/test_iloc.py b/pandas/tests/series/indexing/test_iloc.py
index 64ef2078cbe789..fa85da6a70d62f 100644
--- a/pandas/tests/series/indexing/test_iloc.py
+++ b/pandas/tests/series/indexing/test_iloc.py
@@ -3,8 +3,9 @@
 
 import numpy as np
 
-from pandas import Series
 from pandas.compat import lrange, range
+
+from pandas import Series
 from pandas.util.testing import assert_almost_equal, assert_series_equal
 
 
diff --git a/pandas/tests/series/indexing/test_indexing.py b/pandas/tests/series/indexing/test_indexing.py
index e926e477d0bc40..1582bd119c806c 100644
--- a/pandas/tests/series/indexing/test_indexing.py
+++ b/pandas/tests/series/indexing/test_indexing.py
@@ -8,16 +8,18 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import (
-    Categorical, DataFrame, MultiIndex, Series, Timedelta, Timestamp
-)
 from pandas.compat import lrange, range
+
 from pandas.core.dtypes.common import is_scalar
-from pandas.tseries.offsets import BDay
+
+import pandas as pd
+from pandas import (
+    Categorical, DataFrame, MultiIndex, Series, Timedelta, Timestamp)
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
+from pandas.tseries.offsets import BDay
+
 
 def test_basic_indexing():
     s = Series(np.random.randn(5), index=['a', 'b', 'a', 'a', 'b'])
diff --git a/pandas/tests/series/indexing/test_loc.py b/pandas/tests/series/indexing/test_loc.py
index 596b5d022c68df..36c26267ecd5f3 100644
--- a/pandas/tests/series/indexing/test_loc.py
+++ b/pandas/tests/series/indexing/test_loc.py
@@ -4,9 +4,10 @@
 import numpy as np
 import pytest
 
+from pandas.compat import lrange
+
 import pandas as pd
 from pandas import Series, Timestamp
-from pandas.compat import lrange
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/indexing/test_numeric.py b/pandas/tests/series/indexing/test_numeric.py
index 0b61274801de1f..da0e15b8a96fc7 100644
--- a/pandas/tests/series/indexing/test_numeric.py
+++ b/pandas/tests/series/indexing/test_numeric.py
@@ -4,10 +4,11 @@
 import numpy as np
 import pytest
 
+from pandas.compat import lrange, range
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DataFrame, Index, Series
-from pandas.compat import lrange, range
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/test_alter_axes.py b/pandas/tests/series/test_alter_axes.py
index 5193307a3c256d..be3d0cd6d929c3 100644
--- a/pandas/tests/series/test_alter_axes.py
+++ b/pandas/tests/series/test_alter_axes.py
@@ -6,10 +6,11 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, MultiIndex, RangeIndex, Series
 from pandas.compat import lrange, range, zip
 
+from pandas import DataFrame, Index, MultiIndex, RangeIndex, Series
+import pandas.util.testing as tm
+
 
 class TestSeriesAlterAxes(object):
 
diff --git a/pandas/tests/series/test_analytics.py b/pandas/tests/series/test_analytics.py
index c84cf2ee50e4b6..3f14c80e77dd03 100644
--- a/pandas/tests/series/test_analytics.py
+++ b/pandas/tests/series/test_analytics.py
@@ -1,30 +1,29 @@
 # coding=utf-8
 # pylint: disable-msg=E1101,W0612
 
-import operator
 from distutils.version import LooseVersion
 from itertools import product
+import operator
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
-import pandas as pd
-import pandas.core.nanops as nanops
+from pandas.compat import PY35, lrange, range
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import (
     Categorical, CategoricalIndex, DataFrame, Series, bdate_range, compat,
-    date_range, isna, notna
-)
-from pandas.compat import PY35, lrange, range
+    date_range, isna, notna)
 from pandas.core.index import MultiIndex
 from pandas.core.indexes.datetimes import Timestamp
 from pandas.core.indexes.timedeltas import Timedelta
+import pandas.core.nanops as nanops
+import pandas.util.testing as tm
 from pandas.util.testing import (
     assert_almost_equal, assert_frame_equal, assert_index_equal,
-    assert_series_equal
-)
+    assert_series_equal)
 
 from .common import TestData
 
diff --git a/pandas/tests/series/test_api.py b/pandas/tests/series/test_api.py
index 32181fe3dad39d..bd0d02014dcdb4 100644
--- a/pandas/tests/series/test_api.py
+++ b/pandas/tests/series/test_api.py
@@ -1,24 +1,26 @@
 # coding=utf-8
 # pylint: disable-msg=E1101,W0612
+from collections import OrderedDict
 import pydoc
 import warnings
-from collections import OrderedDict
 
 import numpy as np
 import pytest
 
+import pandas.compat as compat
+from pandas.compat import isidentifier, lzip, range, string_types
+
 import pandas as pd
-import pandas.io.formats.printing as printing
-import pandas.util.testing as tm
 from pandas import (
     Categorical, DataFrame, DatetimeIndex, Index, Series, TimedeltaIndex,
-    compat, date_range, period_range, timedelta_range
-)
-from pandas.compat import isidentifier, lzip, range, string_types
+    date_range, period_range, timedelta_range)
 from pandas.core.arrays import PeriodArray
 from pandas.core.indexes.datetimes import Timestamp
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal, ensure_clean
 
+import pandas.io.formats.printing as printing
+
 from .common import TestData
 
 
diff --git a/pandas/tests/series/test_apply.py b/pandas/tests/series/test_apply.py
index 62a677b82aeb40..f4c8ebe64630cf 100644
--- a/pandas/tests/series/test_apply.py
+++ b/pandas/tests/series/test_apply.py
@@ -7,11 +7,13 @@
 import numpy as np
 import pytest
 
-import pandas as pd
-import pandas.util.testing as tm
-from pandas import DataFrame, Index, Series, compat, isna
+import pandas.compat as compat
 from pandas.compat import lrange
+
+import pandas as pd
+from pandas import DataFrame, Index, Series, isna
 from pandas.conftest import _get_cython_table_params
+import pandas.util.testing as tm
 from pandas.util.testing import assert_frame_equal, assert_series_equal
 
 
diff --git a/pandas/tests/series/test_arithmetic.py b/pandas/tests/series/test_arithmetic.py
index e781488a799ec0..979775633f644f 100644
--- a/pandas/tests/series/test_arithmetic.py
+++ b/pandas/tests/series/test_arithmetic.py
@@ -1,14 +1,14 @@
 # -*- coding: utf-8 -*-
-import operator
 from datetime import timedelta
+import operator
 
 import numpy as np
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import Series, compat
 from pandas.core.indexes.period import IncompatibleFrequency
+import pandas.util.testing as tm
 
 
 def _permute(obj):
diff --git a/pandas/tests/series/test_asof.py b/pandas/tests/series/test_asof.py
index 2d18b617509962..488fc894b953e5 100644
--- a/pandas/tests/series/test_asof.py
+++ b/pandas/tests/series/test_asof.py
@@ -3,8 +3,8 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Series, Timestamp, date_range, isna, notna, offsets
+import pandas.util.testing as tm
 
 
 class TestSeriesAsof():
diff --git a/pandas/tests/series/test_combine_concat.py b/pandas/tests/series/test_combine_concat.py
index 539e3c560b662f..a685eb7e9fbd3f 100644
--- a/pandas/tests/series/test_combine_concat.py
+++ b/pandas/tests/series/test_combine_concat.py
@@ -4,12 +4,12 @@
 from datetime import datetime
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DataFrame, DatetimeIndex, Series, compat, date_range
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/test_constructors.py b/pandas/tests/series/test_constructors.py
index 7595b1278a2916..494321c5190a63 100644
--- a/pandas/tests/series/test_constructors.py
+++ b/pandas/tests/series/test_constructors.py
@@ -5,24 +5,24 @@
 from datetime import datetime, timedelta
 
 import numpy as np
+from numpy import nan
 import numpy.ma as ma
 import pytest
-from numpy import nan
+
+from pandas._libs import lib
+from pandas._libs.tslib import iNaT
+from pandas.compat import PY36, long, lrange, range, zip
+
+from pandas.core.dtypes.common import (
+    is_categorical_dtype, is_datetime64tz_dtype)
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
     Categorical, DataFrame, Index, IntervalIndex, MultiIndex, NaT, Series,
-    Timestamp, date_range, isna, period_range, timedelta_range
-)
-from pandas._libs import lib
-from pandas._libs.tslib import iNaT
+    Timestamp, date_range, isna, period_range, timedelta_range)
 from pandas.api.types import CategoricalDtype
-from pandas.compat import PY36, long, lrange, range, zip
 from pandas.core.arrays import period_array
-from pandas.core.dtypes.common import (
-    is_categorical_dtype, is_datetime64tz_dtype
-)
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/test_datetime_values.py b/pandas/tests/series/test_datetime_values.py
index 618745eb25a5af..1fd95c4205b0e4 100644
--- a/pandas/tests/series/test_datetime_values.py
+++ b/pandas/tests/series/test_datetime_values.py
@@ -2,24 +2,25 @@
 # pylint: disable-msg=E1101,W0612
 
 import calendar
+from datetime import date, datetime, time
 import locale
 import unicodedata
-from datetime import date, datetime, time
 
 import numpy as np
 import pytest
 import pytz
 
+from pandas._libs.tslibs.timezones import maybe_get_tz
+
+from pandas.core.dtypes.common import is_integer_dtype, is_list_like
+
 import pandas as pd
-import pandas.core.common as com
-import pandas.util.testing as tm
 from pandas import (
     DataFrame, DatetimeIndex, Index, PeriodIndex, Series, TimedeltaIndex,
-    bdate_range, compat, date_range, period_range, timedelta_range
-)
-from pandas._libs.tslibs.timezones import maybe_get_tz
+    bdate_range, compat, date_range, period_range, timedelta_range)
 from pandas.core.arrays import PeriodArray
-from pandas.core.dtypes.common import is_integer_dtype, is_list_like
+import pandas.core.common as com
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/test_dtypes.py b/pandas/tests/series/test_dtypes.py
index 64184a6465ba3f..a3aaabb70ae8c1 100644
--- a/pandas/tests/series/test_dtypes.py
+++ b/pandas/tests/series/test_dtypes.py
@@ -1,23 +1,23 @@
 # coding=utf-8
 # pylint: disable-msg=E1101,W0612
 
+from datetime import datetime, timedelta
 import string
 import sys
-from datetime import datetime, timedelta
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
-import pandas as pd
 import pandas._libs.tslib as tslib
-import pandas.util.testing as tm
+import pandas.compat as compat
+from pandas.compat import lrange, range, u
+
+import pandas as pd
 from pandas import (
-    Categorical, DataFrame, Index, Series, Timedelta, Timestamp, compat,
-    date_range
-)
+    Categorical, DataFrame, Index, Series, Timedelta, Timestamp, date_range)
 from pandas.api.types import CategoricalDtype
-from pandas.compat import lrange, range, u
+import pandas.util.testing as tm
 
 
 class TestSeriesDtypes(object):
diff --git a/pandas/tests/series/test_internals.py b/pandas/tests/series/test_internals.py
index f6759f039ed98b..8e3b0d19447a1d 100644
--- a/pandas/tests/series/test_internals.py
+++ b/pandas/tests/series/test_internals.py
@@ -4,14 +4,15 @@
 from datetime import datetime
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
-import pandas as pd
 import pandas._libs.lib as lib
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import Series
 from pandas.core.indexes.datetimes import Timestamp
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/test_io.py b/pandas/tests/series/test_io.py
index 033816dd8ee4b8..5749b0c6551d60 100644
--- a/pandas/tests/series/test_io.py
+++ b/pandas/tests/series/test_io.py
@@ -7,14 +7,15 @@
 import numpy as np
 import pytest
 
+from pandas.compat import StringIO, u
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DataFrame, Series
-from pandas.compat import StringIO, u
-from pandas.io.common import _get_handle
+import pandas.util.testing as tm
 from pandas.util.testing import (
-    assert_almost_equal, assert_frame_equal, assert_series_equal, ensure_clean
-)
+    assert_almost_equal, assert_frame_equal, assert_series_equal, ensure_clean)
+
+from pandas.io.common import _get_handle
 
 
 class TestSeriesToCSV():
diff --git a/pandas/tests/series/test_missing.py b/pandas/tests/series/test_missing.py
index e89bcae052115c..c38b7c0083a218 100644
--- a/pandas/tests/series/test_missing.py
+++ b/pandas/tests/series/test_missing.py
@@ -5,21 +5,21 @@
 from distutils.version import LooseVersion
 
 import numpy as np
+from numpy import nan
 import pytest
 import pytz
-from numpy import nan
 
-import pandas as pd
+from pandas._libs.tslib import iNaT
+from pandas.compat import range
+from pandas.errors import PerformanceWarning
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import (
     Categorical, DataFrame, Index, IntervalIndex, MultiIndex, NaT, Series,
-    Timestamp, date_range, isna
-)
-from pandas._libs.tslib import iNaT
-from pandas.compat import range
+    Timestamp, date_range, isna)
 from pandas.core.series import remove_na
-from pandas.errors import PerformanceWarning
+import pandas.util.testing as tm
 from pandas.util.testing import assert_frame_equal, assert_series_equal
 
 try:
diff --git a/pandas/tests/series/test_operators.py b/pandas/tests/series/test_operators.py
index 082ed5e0f5123c..35bd99ff2eda81 100644
--- a/pandas/tests/series/test_operators.py
+++ b/pandas/tests/series/test_operators.py
@@ -1,25 +1,24 @@
 # coding=utf-8
 # pylint: disable-msg=E1101,W0612
 
-import operator
 from datetime import datetime, timedelta
+import operator
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
+
+import pandas.compat as compat
+from pandas.compat import range
 
 import pandas as pd
-import pandas.core.nanops as nanops
-import pandas.util.testing as tm
 from pandas import (
-    Categorical, DataFrame, Index, NaT, Series, bdate_range, compat,
-    date_range, isna
-)
-from pandas.compat import range
+    Categorical, DataFrame, Index, NaT, Series, bdate_range, date_range, isna)
 from pandas.core import ops
+import pandas.core.nanops as nanops
+import pandas.util.testing as tm
 from pandas.util.testing import (
-    assert_almost_equal, assert_frame_equal, assert_series_equal
-)
+    assert_almost_equal, assert_frame_equal, assert_series_equal)
 
 from .common import TestData
 
diff --git a/pandas/tests/series/test_period.py b/pandas/tests/series/test_period.py
index 88a5ff261fbb4e..ce620db8d9c1b1 100644
--- a/pandas/tests/series/test_period.py
+++ b/pandas/tests/series/test_period.py
@@ -2,9 +2,9 @@
 import pytest
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import DataFrame, Period, Series, period_range
 from pandas.core.arrays import PeriodArray
+import pandas.util.testing as tm
 
 
 class TestSeriesPeriod(object):
diff --git a/pandas/tests/series/test_quantile.py b/pandas/tests/series/test_quantile.py
index 1a4c72b9f35fc5..027814c618303f 100644
--- a/pandas/tests/series/test_quantile.py
+++ b/pandas/tests/series/test_quantile.py
@@ -4,11 +4,12 @@
 import numpy as np
 import pytest
 
+from pandas.core.dtypes.common import is_integer
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import Index, Series
-from pandas.core.dtypes.common import is_integer
 from pandas.core.indexes.datetimes import Timestamp
+import pandas.util.testing as tm
 
 from .common import TestData
 
diff --git a/pandas/tests/series/test_rank.py b/pandas/tests/series/test_rank.py
index afe1155932ea44..40a30cc8cf09a3 100644
--- a/pandas/tests/series/test_rank.py
+++ b/pandas/tests/series/test_rank.py
@@ -3,17 +3,19 @@
 from itertools import chain
 
 import numpy as np
-import pytest
 from numpy import nan
+import pytest
 
-import pandas.util._test_decorators as td
-import pandas.util.testing as tm
-from pandas import NaT, Series, Timestamp, compat, date_range
 from pandas._libs.algos import Infinity, NegInfinity
 from pandas._libs.tslib import iNaT
-from pandas.api.types import CategoricalDtype
+import pandas.compat as compat
 from pandas.compat import product
+import pandas.util._test_decorators as td
+
+from pandas import NaT, Series, Timestamp, date_range
+from pandas.api.types import CategoricalDtype
 from pandas.tests.series.common import TestData
+import pandas.util.testing as tm
 from pandas.util.testing import assert_series_equal
 
 
diff --git a/pandas/tests/series/test_replace.py b/pandas/tests/series/test_replace.py
index 54318aa9a4a34a..67c75f43e030c1 100644
--- a/pandas/tests/series/test_replace.py
+++ b/pandas/tests/series/test_replace.py
@@ -4,8 +4,9 @@
 import numpy as np
 import pytest
 
-import pandas as pd
 import pandas._libs.lib as lib
+
+import pandas as pd
 import pandas.util.testing as tm
 
 from .common import TestData
diff --git a/pandas/tests/series/test_repr.py b/pandas/tests/series/test_repr.py
index 8e89dd0f44a4d3..ef962747466559 100644
--- a/pandas/tests/series/test_repr.py
+++ b/pandas/tests/series/test_repr.py
@@ -1,20 +1,21 @@
 # coding=utf-8
 # pylint: disable-msg=E1101,W0612
 
-import sys
 from datetime import datetime, timedelta
+import sys
 
 import numpy as np
 
+import pandas.compat as compat
+from pandas.compat import lrange, range, u
+
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import (
-    Categorical, DataFrame, Index, Series, compat, date_range, option_context,
-    period_range, timedelta_range
-)
-from pandas.compat import lrange, range, u
+    Categorical, DataFrame, Index, Series, date_range, option_context,
+    period_range, timedelta_range)
 from pandas.core.base import StringMixin
 from pandas.core.index import MultiIndex
+import pandas.util.testing as tm
 
 from .common import TestData
 
diff --git a/pandas/tests/series/test_sorting.py b/pandas/tests/series/test_sorting.py
index f15160d9ebab6e..ef6998c1a3e12d 100644
--- a/pandas/tests/series/test_sorting.py
+++ b/pandas/tests/series/test_sorting.py
@@ -5,8 +5,8 @@
 import numpy as np
 import pytest
 
-import pandas.util.testing as tm
 from pandas import Categorical, DataFrame, IntervalIndex, MultiIndex, Series
+import pandas.util.testing as tm
 from pandas.util.testing import assert_almost_equal, assert_series_equal
 
 from .common import TestData
diff --git a/pandas/tests/series/test_subclass.py b/pandas/tests/series/test_subclass.py
index f48b4e6a7510f5..68a162ee4c287e 100644
--- a/pandas/tests/series/test_subclass.py
+++ b/pandas/tests/series/test_subclass.py
@@ -3,8 +3,8 @@
 import numpy as np
 
 import pandas as pd
-import pandas.util.testing as tm
 from pandas import SparseDtype
+import pandas.util.testing as tm
 
 
 class TestSeriesSubclassing(object):
diff --git a/pandas/tests/series/test_timeseries.py b/pandas/tests/series/test_timeseries.py
index b46570fcfb1a5b..21f80f181c34df 100644
--- a/pandas/tests/series/test_timeseries.py
+++ b/pandas/tests/series/test_timeseries.py
@@ -6,23 +6,23 @@
 import numpy as np
 import pytest
 
-import pandas as pd
+from pandas._libs.tslib import iNaT
+from pandas.compat import StringIO, lrange, product
+from pandas.errors import NullFrequencyError
 import pandas.util._test_decorators as td
-import pandas.util.testing as tm
+
+import pandas as pd
 from pandas import (
     DataFrame, Index, NaT, Series, Timestamp, concat, date_range, offsets,
-    timedelta_range, to_datetime
-)
-from pandas._libs.tslib import iNaT
-from pandas.compat import StringIO, lrange, product
+    timedelta_range, to_datetime)
 from pandas.core.indexes.datetimes import DatetimeIndex
 from pandas.core.indexes.timedeltas import TimedeltaIndex
-from pandas.errors import NullFrequencyError
 from pandas.tests.series.common import TestData
-from pandas.tseries.offsets import BDay, BMonthEnd
+import pandas.util.testing as tm
 from pandas.util.testing import (
-    assert_almost_equal, assert_frame_equal, assert_series_equal
-)
+    assert_almost_equal, assert_frame_equal, assert_series_equal)
+
+from pandas.tseries.offsets import BDay, BMonthEnd
 
 
 def _simple_ts(start, end, freq='D'):
diff --git a/pandas/tests/series/test_timezones.py b/pandas/tests/series/test_timezones.py
index 0b65af6831d070..3c9701758f12cf 100644
--- a/pandas/tests/series/test_timezones.py
+++ b/pandas/tests/series/test_timezones.py
@@ -4,16 +4,17 @@
 """
 from datetime import datetime
 
+from dateutil.tz import tzoffset
 import numpy as np
 import pytest
 import pytz
-from dateutil.tz import tzoffset
 
-import pandas.util.testing as tm
-from pandas import DatetimeIndex, Index, NaT, Series, Timestamp
 from pandas._libs.tslibs import conversion, timezones
 from pandas.compat import lrange
+
+from pandas import DatetimeIndex, Index, NaT, Series, Timestamp
 from pandas.core.indexes.datetimes import date_range
+import pandas.util.testing as tm
 
 
 class TestSeriesTimezones(object):
diff --git a/pandas/tests/tslibs/test_liboffsets.py b/pandas/tests/tslibs/test_liboffsets.py
index 50d8f546d8e58f..388df6453634e0 100644
--- a/pandas/tests/tslibs/test_liboffsets.py
+++ b/pandas/tests/tslibs/test_liboffsets.py
@@ -7,9 +7,10 @@
 import pytest
 
 import pandas._libs.tslibs.offsets as liboffsets
-from pandas import Timestamp
 from pandas._libs.tslibs.offsets import roll_qtrday
 
+from pandas import Timestamp
+
 
 def test_get_lastbday():
     dt = datetime(2017, 11, 30)
diff --git a/pandas/tests/tslibs/test_timedeltas.py b/pandas/tests/tslibs/test_timedeltas.py
index 939c2b828a75f5..50e64bb7c20822 100644
--- a/pandas/tests/tslibs/test_timedeltas.py
+++ b/pandas/tests/tslibs/test_timedeltas.py
@@ -2,9 +2,10 @@
 import numpy as np
 import pytest
 
-import pandas as pd
 from pandas._libs.tslibs.timedeltas import delta_to_nanoseconds
 
+import pandas as pd
+
 
 def test_delta_to_nanoseconds():
     obj = np.timedelta64(14, 'D')
diff --git a/pandas/tseries/api.py b/pandas/tseries/api.py
index 982a0e715e3607..2094791ecdc609 100644
--- a/pandas/tseries/api.py
+++ b/pandas/tseries/api.py
@@ -4,5 +4,5 @@
 
 # flake8: noqa
 
-import pandas.tseries.offsets as offsets
 from pandas.tseries.frequencies import infer_freq
+import pandas.tseries.offsets as offsets
diff --git a/setup.cfg b/setup.cfg
index e1d0dc84f464a7..1cfefa1bbaadd2 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -77,11 +77,17 @@ exclude_lines =
 directory = coverage_html_report
 
 [isort]
+known_pre_core=pandas._libs,pandas.util._*,pandas.compat,pandas.errors
+known_dtypes=pandas.core.dtypes
+known_post_core=pandas.tseries,pandas.io,pandas.plotting
+sections=FUTURE,STDLIB,THIRDPARTY,PRE_CORE,DTYPES,FIRSTPARTY,POST_CORE,LOCALFOLDER
+
 known_first_party=pandas
-known_third_party=Cython,numpy,python-dateutil,pytz
-multi_line_output=5
+known_third_party=Cython,numpy,python-dateutil,pytz,pyarrow
+multi_line_output=4
 force_grid_wrap=0
 combine_as_imports=True
+force_sort_within_sections=True
 skip=
     pandas/lib.py,
     pandas/tslib.py,