diff --git a/pandas/core/arrays/base.py b/pandas/core/arrays/base.py
index f842d1237cb14..eb2fef482ff17 100644
--- a/pandas/core/arrays/base.py
+++ b/pandas/core/arrays/base.py
@@ -5,16 +5,18 @@
    This is an experimental API and subject to breaking changes
    without warning.
 """
-import numpy as np
-
 import operator
 
-from pandas.core.dtypes.generic import ABCSeries, ABCIndexClass
-from pandas.errors import AbstractMethodError
+import numpy as np
+
+from pandas.compat import PY3, set_function_name
 from pandas.compat.numpy import function as nv
-from pandas.compat import set_function_name, PY3
-from pandas.core import ops
+from pandas.errors import AbstractMethodError
+
 from pandas.core.dtypes.common import is_list_like
+from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
+
+from pandas.core import ops
 
 _not_implemented_message = "{} does not implement {}."
 
diff --git a/pandas/core/arrays/categorical.py b/pandas/core/arrays/categorical.py
index 276ef6426a51b..6dc3a960dc817 100644
--- a/pandas/core/arrays/categorical.py
+++ b/pandas/core/arrays/categorical.py
@@ -1,61 +1,46 @@
 # pylint: disable=E1101,W0232
 
-import numpy as np
-from warnings import warn
 import textwrap
+from warnings import warn
 
-from pandas import compat
-from pandas.compat import u, lzip
-from pandas._libs import lib, algos as libalgos
+import numpy as np
+
+from pandas._libs import algos as libalgos, lib
+import pandas.compat as compat
+from pandas.compat import lzip, u
+from pandas.compat.numpy import function as nv
+from pandas.util._decorators import (
+    Appender, Substitution, cache_readonly, deprecate_kwarg)
+from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
 
-from pandas.core.dtypes.generic import (
-    ABCSeries, ABCIndexClass, ABCCategoricalIndex)
-from pandas.core.dtypes.missing import isna, notna
-from pandas.core.dtypes.inference import is_hashable
 from pandas.core.dtypes.cast import (
-    maybe_infer_to_datetimelike,
-    coerce_indexer_dtype)
-from pandas.core.dtypes.dtypes import CategoricalDtype
+    coerce_indexer_dtype, maybe_infer_to_datetimelike)
 from pandas.core.dtypes.common import (
-    ensure_int64,
-    ensure_object,
-    ensure_platform_int,
-    is_extension_array_dtype,
-    is_dtype_equal,
-    is_datetimelike,
-    is_datetime64_dtype,
-    is_timedelta64_dtype,
-    is_categorical,
-    is_categorical_dtype,
-    is_float_dtype,
-    is_integer_dtype,
-    is_object_dtype,
-    is_list_like, is_sequence,
-    is_scalar, is_iterator,
-    is_dict_like)
-
-from pandas.core.algorithms import factorize, take_1d, unique1d, take
+    ensure_int64, ensure_object, ensure_platform_int, is_categorical,
+    is_categorical_dtype, is_datetime64_dtype, is_datetimelike, is_dict_like,
+    is_dtype_equal, is_extension_array_dtype, is_float_dtype, is_integer_dtype,
+    is_iterator, is_list_like, is_object_dtype, is_scalar, is_sequence,
+    is_timedelta64_dtype)
+from pandas.core.dtypes.dtypes import CategoricalDtype
+from pandas.core.dtypes.generic import (
+    ABCCategoricalIndex, ABCIndexClass, ABCSeries)
+from pandas.core.dtypes.inference import is_hashable
+from pandas.core.dtypes.missing import isna, notna
+
 from pandas.core.accessor import PandasDelegate, delegate_names
-from pandas.core.base import (PandasObject,
-                              NoNewAttributesMixin, _shared_docs)
+import pandas.core.algorithms as algorithms
+from pandas.core.algorithms import factorize, take, take_1d, unique1d
+from pandas.core.base import NoNewAttributesMixin, PandasObject, _shared_docs
 import pandas.core.common as com
+from pandas.core.config import get_option
 from pandas.core.missing import interpolate_2d
-from pandas.compat.numpy import function as nv
-from pandas.util._decorators import (
-    Appender, cache_readonly, deprecate_kwarg, Substitution)
-
-import pandas.core.algorithms as algorithms
-
 from pandas.core.sorting import nargsort
 
 from pandas.io.formats import console
 from pandas.io.formats.terminal import get_terminal_size
-from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
-from pandas.core.config import get_option
 
 from .base import ExtensionArray
 
-
 _take_msg = textwrap.dedent("""\
     Interpreting negative values in 'indexer' as missing values.
     In the future, this will change to meaning positional indices
diff --git a/pandas/core/arrays/datetimelike.py b/pandas/core/arrays/datetimelike.py
index 631257b7a5264..4e784d9c89c5f 100644
--- a/pandas/core/arrays/datetimelike.py
+++ b/pandas/core/arrays/datetimelike.py
@@ -5,44 +5,33 @@
 
 import numpy as np
 
-from pandas._libs import lib, iNaT, NaT
+from pandas._libs import NaT, iNaT, lib
 from pandas._libs.tslibs import timezones
-from pandas._libs.tslibs.timedeltas import delta_to_nanoseconds, Timedelta
-from pandas._libs.tslibs.timestamps import maybe_integer_op_deprecated
 from pandas._libs.tslibs.period import (
-    Period, DIFFERENT_FREQ_INDEX, IncompatibleFrequency)
-
+    DIFFERENT_FREQ_INDEX, IncompatibleFrequency, Period)
+from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
+from pandas._libs.tslibs.timestamps import maybe_integer_op_deprecated
+import pandas.compat as compat
 from pandas.errors import (
     AbstractMethodError, NullFrequencyError, PerformanceWarning)
-from pandas import compat
-
-from pandas.tseries import frequencies
-from pandas.tseries.offsets import Tick, DateOffset
+from pandas.util._decorators import deprecate_kwarg
 
 from pandas.core.dtypes.common import (
-    pandas_dtype,
-    needs_i8_conversion,
-    is_list_like,
-    is_offsetlike,
-    is_extension_array_dtype,
-    is_datetime64_dtype,
-    is_datetime64_any_dtype,
-    is_datetime64tz_dtype,
-    is_float_dtype,
-    is_integer_dtype,
-    is_bool_dtype,
-    is_period_dtype,
-    is_timedelta64_dtype,
-    is_object_dtype)
-from pandas.core.dtypes.generic import ABCSeries, ABCDataFrame, ABCIndexClass
+    is_bool_dtype, is_datetime64_any_dtype, is_datetime64_dtype,
+    is_datetime64tz_dtype, is_extension_array_dtype, is_float_dtype,
+    is_integer_dtype, is_list_like, is_object_dtype, is_offsetlike,
+    is_period_dtype, is_timedelta64_dtype, needs_i8_conversion, pandas_dtype)
 from pandas.core.dtypes.dtypes import DatetimeTZDtype
+from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
 from pandas.core.dtypes.missing import isna
 
-import pandas.core.common as com
 from pandas.core.algorithms import checked_add_with_arr, take, unique1d
+import pandas.core.common as com
+
+from pandas.tseries import frequencies
+from pandas.tseries.offsets import DateOffset, Tick
 
 from .base import ExtensionOpsMixin
-from pandas.util._decorators import deprecate_kwarg
 
 
 def _make_comparison_op(cls, op):
diff --git a/pandas/core/arrays/datetimes.py b/pandas/core/arrays/datetimes.py
index c56e994e0ca2f..2187ff28844a0 100644
--- a/pandas/core/arrays/datetimes.py
+++ b/pandas/core/arrays/datetimes.py
@@ -6,35 +6,28 @@
 from pytz import utc
 
 from pandas._libs import lib, tslib
-from pandas._libs.tslib import Timestamp, NaT, iNaT
+from pandas._libs.tslib import NaT, Timestamp, iNaT
 from pandas._libs.tslibs import (
-    ccalendar, normalize_date,
-    conversion, fields, timezones,
-    resolution as libresolution)
-
-from pandas.util._decorators import cache_readonly, Appender
+    ccalendar, conversion, fields, normalize_date, resolution as libresolution,
+    timezones)
+import pandas.compat as compat
 from pandas.errors import PerformanceWarning
-from pandas import compat
+from pandas.util._decorators import Appender, cache_readonly
 
 from pandas.core.dtypes.common import (
-    _NS_DTYPE,
-    is_object_dtype,
-    is_int64_dtype,
-    is_datetime64tz_dtype,
-    is_datetime64_dtype)
+    _NS_DTYPE, is_datetime64_dtype, is_datetime64tz_dtype, is_int64_dtype,
+    is_object_dtype)
 from pandas.core.dtypes.dtypes import DatetimeTZDtype
-from pandas.core.dtypes.missing import isna
 from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
+from pandas.core.dtypes.missing import isna
 
-import pandas.core.common as com
-from pandas.core.algorithms import checked_add_with_arr
 from pandas.core import ops
-
-from pandas.tseries.frequencies import to_offset, get_period_alias
-from pandas.tseries.offsets import Tick, generate_range
-
+from pandas.core.algorithms import checked_add_with_arr
 from pandas.core.arrays import datetimelike as dtl
+import pandas.core.common as com
 
+from pandas.tseries.frequencies import get_period_alias, to_offset
+from pandas.tseries.offsets import Tick, generate_range
 
 _midnight = time(0, 0)
 
diff --git a/pandas/core/arrays/integer.py b/pandas/core/arrays/integer.py
index 9e045a7785660..e9d51aaea4218 100644
--- a/pandas/core/arrays/integer.py
+++ b/pandas/core/arrays/integer.py
@@ -1,31 +1,27 @@
+import copy
 import sys
 import warnings
-import copy
-import numpy as np
 
+import numpy as np
 
 from pandas._libs import lib
+from pandas.compat import range, set_function_name, string_types, u
 from pandas.util._decorators import cache_readonly
-from pandas.compat import u, range, string_types
-from pandas.compat import set_function_name
 
-from pandas.core import nanops
+from pandas.core.dtypes.base import ExtensionDtype
 from pandas.core.dtypes.cast import astype_nansafe
-from pandas.core.dtypes.generic import ABCSeries, ABCIndexClass
 from pandas.core.dtypes.common import (
-    is_integer, is_scalar, is_float,
-    is_bool_dtype,
-    is_float_dtype,
-    is_integer_dtype,
-    is_object_dtype,
-    is_list_like)
-from pandas.core.arrays import ExtensionArray, ExtensionOpsMixin
-from pandas.core.dtypes.base import ExtensionDtype
+    is_bool_dtype, is_float, is_float_dtype, is_integer, is_integer_dtype,
+    is_list_like, is_object_dtype, is_scalar)
 from pandas.core.dtypes.dtypes import register_extension_dtype
+from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
 from pandas.core.dtypes.missing import isna, notna
 
+from pandas.core import nanops
+from pandas.core.arrays import ExtensionArray, ExtensionOpsMixin
+
 from pandas.io.formats.printing import (
-    format_object_summary, format_object_attrs, default_pprint)
+    default_pprint, format_object_attrs, format_object_summary)
 
 
 class _IntegerDtype(ExtensionDtype):
diff --git a/pandas/core/arrays/interval.py b/pandas/core/arrays/interval.py
index 90118cd300a22..70be850481d85 100644
--- a/pandas/core/arrays/interval.py
+++ b/pandas/core/arrays/interval.py
@@ -1,31 +1,30 @@
+from operator import le, lt
 import textwrap
-import numpy as np
 
-from operator import le, lt
+import numpy as np
 
-from pandas._libs.interval import (Interval, IntervalMixin,
-                                   intervals_to_interval_bounds)
+from pandas._libs.interval import (
+    Interval, IntervalMixin, intervals_to_interval_bounds)
 from pandas.compat import add_metaclass
 from pandas.compat.numpy import function as nv
-import pandas.core.common as com
-from pandas.core.config import get_option
+from pandas.util._decorators import Appender
+from pandas.util._doctools import _WritableDoc
+
 from pandas.core.dtypes.cast import maybe_convert_platform
-from pandas.core.dtypes.common import (is_categorical_dtype, is_float_dtype,
-                                       is_integer_dtype, is_interval_dtype,
-                                       is_scalar, is_string_dtype,
-                                       is_datetime64_any_dtype,
-                                       is_timedelta64_dtype, is_interval,
-                                       pandas_dtype)
+from pandas.core.dtypes.common import (
+    is_categorical_dtype, is_datetime64_any_dtype, is_float_dtype,
+    is_integer_dtype, is_interval, is_interval_dtype, is_scalar,
+    is_string_dtype, is_timedelta64_dtype, pandas_dtype)
 from pandas.core.dtypes.dtypes import IntervalDtype
-from pandas.core.dtypes.generic import (ABCDatetimeIndex, ABCPeriodIndex,
-                                        ABCSeries, ABCIntervalIndex,
-                                        ABCInterval)
+from pandas.core.dtypes.generic import (
+    ABCDatetimeIndex, ABCInterval, ABCIntervalIndex, ABCPeriodIndex, ABCSeries)
 from pandas.core.dtypes.missing import isna, notna
+
+import pandas.core.common as com
+from pandas.core.config import get_option
 from pandas.core.indexes.base import Index, ensure_index
-from pandas.util._decorators import Appender
-from pandas.util._doctools import _WritableDoc
 
-from . import ExtensionArray, Categorical
+from . import Categorical, ExtensionArray
 
 _VALID_CLOSED = {'left', 'right', 'both', 'neither'}
 _interval_shared_docs = {}
diff --git a/pandas/core/arrays/period.py b/pandas/core/arrays/period.py
index d9989b1ac36c0..53629dca4d391 100644
--- a/pandas/core/arrays/period.py
+++ b/pandas/core/arrays/period.py
@@ -4,48 +4,35 @@
 
 import numpy as np
 
-from pandas import compat
-from pandas.compat.numpy import function as nv
 from pandas._libs.tslib import NaT, iNaT
-from pandas._libs.tslibs.period import (
-    Period, IncompatibleFrequency, DIFFERENT_FREQ_INDEX,
-    get_period_field_arr, period_asfreq_arr,
-)
 from pandas._libs.tslibs import period as libperiod
-from pandas._libs.tslibs.timedeltas import delta_to_nanoseconds, Timedelta
 from pandas._libs.tslibs.fields import isleapyear_arr
-from pandas.util._decorators import cache_readonly, Appender
+from pandas._libs.tslibs.period import (
+    DIFFERENT_FREQ_INDEX, IncompatibleFrequency, Period, get_period_field_arr,
+    period_asfreq_arr)
+from pandas._libs.tslibs.timedeltas import Timedelta, delta_to_nanoseconds
+import pandas.compat as compat
+from pandas.compat.numpy import function as nv
+from pandas.util._decorators import Appender, cache_readonly
 from pandas.util._validators import validate_fillna_kwargs
-import pandas.core.algorithms as algos
+
 from pandas.core.dtypes.common import (
-    is_integer_dtype, is_float_dtype, is_period_dtype,
-    pandas_dtype,
-    is_datetime64_dtype,
-    is_categorical_dtype,
-    is_list_like,
-    is_array_like,
-    is_object_dtype,
-    is_string_dtype,
-    is_datetime_or_timedelta_dtype,
-    is_dtype_equal,
-    ensure_object,
-    _TD_DTYPE,
-)
+    _TD_DTYPE, ensure_object, is_array_like, is_categorical_dtype,
+    is_datetime64_dtype, is_datetime_or_timedelta_dtype, is_dtype_equal,
+    is_float_dtype, is_integer_dtype, is_list_like, is_object_dtype,
+    is_period_dtype, is_string_dtype, pandas_dtype)
 from pandas.core.dtypes.dtypes import PeriodDtype
-from pandas.core.dtypes.generic import (
-    ABCSeries, ABCIndexClass, ABCPeriodIndex
-)
+from pandas.core.dtypes.generic import ABCIndexClass, ABCPeriodIndex, ABCSeries
 from pandas.core.dtypes.missing import isna, notna
-from pandas.core.missing import pad_1d, backfill_1d
 
+import pandas.core.algorithms as algos
+from pandas.core.arrays import ExtensionArray, datetimelike as dtl
 import pandas.core.common as com
+from pandas.core.missing import backfill_1d, pad_1d
 
 from pandas.tseries import frequencies
 from pandas.tseries.offsets import Tick
 
-from pandas.core.arrays import ExtensionArray
-from pandas.core.arrays import datetimelike as dtl
-
 
 def _field_accessor(name, alias, docstring=None):
     def f(self):
diff --git a/pandas/core/arrays/timedeltas.py b/pandas/core/arrays/timedeltas.py
index cb630c9b66c20..38e28e8b77359 100644
--- a/pandas/core/arrays/timedeltas.py
+++ b/pandas/core/arrays/timedeltas.py
@@ -5,32 +5,25 @@
 import numpy as np
 
 from pandas._libs import tslibs
-from pandas._libs.tslibs import Timedelta, Timestamp, NaT, iNaT
+from pandas._libs.tslibs import NaT, Timedelta, Timestamp, iNaT
 from pandas._libs.tslibs.fields import get_timedelta_field
 from pandas._libs.tslibs.timedeltas import (
     array_to_timedelta64, parse_timedelta_unit)
+import pandas.compat as compat
 from pandas.util._decorators import Appender
 
-from pandas import compat
-
 from pandas.core.dtypes.common import (
-    _TD_DTYPE,
-    is_object_dtype,
-    is_string_dtype,
-    is_float_dtype,
-    is_integer_dtype,
-    is_timedelta64_dtype,
-    is_datetime64_dtype,
-    is_list_like,
-    ensure_int64)
+    _TD_DTYPE, ensure_int64, is_datetime64_dtype, is_float_dtype,
+    is_integer_dtype, is_list_like, is_object_dtype, is_string_dtype,
+    is_timedelta64_dtype)
 from pandas.core.dtypes.generic import ABCSeries, ABCTimedeltaIndex
 from pandas.core.dtypes.missing import isna
 
-import pandas.core.common as com
 from pandas.core.algorithms import checked_add_with_arr
+import pandas.core.common as com
 
-from pandas.tseries.offsets import Tick
 from pandas.tseries.frequencies import to_offset
+from pandas.tseries.offsets import Tick
 
 from . import datetimelike as dtl
 
diff --git a/pandas/core/internals/blocks.py b/pandas/core/internals/blocks.py
index 1f2a1ee52159e..857bf18c5982b 100644
--- a/pandas/core/internals/blocks.py
+++ b/pandas/core/internals/blocks.py
@@ -1,76 +1,45 @@
 # -*- coding: utf-8 -*-
+from datetime import date, datetime, timedelta
 import functools
-import warnings
 import inspect
 import re
-from datetime import datetime, timedelta, date
+import warnings
 
 import numpy as np
 
-from pandas._libs import lib, tslib, tslibs, internals as libinternals
-from pandas._libs.tslibs import conversion, Timedelta
-
-from pandas import compat
+from pandas._libs import internals as libinternals, lib, tslib, tslibs
+from pandas._libs.tslibs import Timedelta, conversion
+import pandas.compat as compat
 from pandas.compat import range, zip
-
 from pandas.util._validators import validate_bool_kwarg
 
-from pandas.core.dtypes.dtypes import (
-    ExtensionDtype, DatetimeTZDtype,
-    PandasExtensionDtype,
-    CategoricalDtype)
-from pandas.core.dtypes.common import (
-    _TD_DTYPE, _NS_DTYPE,
-    ensure_platform_int,
-    is_integer,
-    is_dtype_equal,
-    is_timedelta64_dtype,
-    is_datetime64_dtype, is_datetimetz,
-    is_categorical, is_categorical_dtype,
-    is_integer_dtype,
-    is_datetime64tz_dtype,
-    is_bool_dtype,
-    is_object_dtype,
-    is_float_dtype,
-    is_numeric_v_string_like, is_extension_type,
-    is_extension_array_dtype,
-    is_list_like,
-    is_re,
-    is_re_compilable,
-    is_sparse,
-    pandas_dtype)
 from pandas.core.dtypes.cast import (
-    maybe_downcast_to_dtype,
-    maybe_upcast,
-    maybe_promote,
-    infer_dtype_from,
-    infer_dtype_from_scalar,
-    soft_convert_objects,
-    maybe_convert_objects,
-    astype_nansafe,
-    find_common_type,
-    maybe_infer_dtype_type)
-from pandas.core.dtypes.missing import (
-    isna, notna, array_equivalent,
-    _isna_compat,
-    is_null_datelike_scalar)
+    astype_nansafe, find_common_type, infer_dtype_from,
+    infer_dtype_from_scalar, maybe_convert_objects, maybe_downcast_to_dtype,
+    maybe_infer_dtype_type, maybe_promote, maybe_upcast, soft_convert_objects)
+from pandas.core.dtypes.common import (
+    _NS_DTYPE, _TD_DTYPE, ensure_platform_int, is_bool_dtype, is_categorical,
+    is_categorical_dtype, is_datetime64_dtype, is_datetime64tz_dtype,
+    is_datetimetz, is_dtype_equal, is_extension_array_dtype, is_extension_type,
+    is_float_dtype, is_integer, is_integer_dtype, is_list_like,
+    is_numeric_v_string_like, is_object_dtype, is_re, is_re_compilable,
+    is_sparse, is_timedelta64_dtype, pandas_dtype)
 import pandas.core.dtypes.concat as _concat
+from pandas.core.dtypes.dtypes import (
+    CategoricalDtype, DatetimeTZDtype, ExtensionDtype, PandasExtensionDtype)
 from pandas.core.dtypes.generic import (
-    ABCSeries,
-    ABCDatetimeIndex,
-    ABCExtensionArray,
-    ABCIndexClass)
+    ABCDatetimeIndex, ABCExtensionArray, ABCIndexClass, ABCSeries)
+from pandas.core.dtypes.missing import (
+    _isna_compat, array_equivalent, is_null_datelike_scalar, isna, notna)
 
-import pandas.core.common as com
 import pandas.core.algorithms as algos
-import pandas.core.missing as missing
-from pandas.core.base import PandasObject
-
 from pandas.core.arrays import Categorical
-
+from pandas.core.base import PandasObject
+import pandas.core.common as com
 from pandas.core.indexes.datetimes import DatetimeIndex
 from pandas.core.indexes.timedeltas import TimedeltaIndex
 from pandas.core.indexing import check_setitem_lengths
+import pandas.core.missing as missing
 
 from pandas.io.formats.printing import pprint_thing
 
diff --git a/pandas/core/internals/concat.py b/pandas/core/internals/concat.py
index dfb7408384038..2fb533478b2f3 100644
--- a/pandas/core/internals/concat.py
+++ b/pandas/core/internals/concat.py
@@ -1,23 +1,19 @@
 # -*- coding: utf-8 -*-
 # TODO: Needs a better name; too many modules are already called "concat"
-import copy
 from collections import defaultdict
+import copy
 
 import numpy as np
 
-from pandas._libs import tslibs, internals as libinternals
+from pandas._libs import internals as libinternals, tslibs
 from pandas.util._decorators import cache_readonly
 
-from pandas.core.dtypes.missing import isna
-from pandas.core.dtypes.common import (
-    is_timedelta64_dtype,
-    is_datetime64_dtype, is_datetimetz,
-    is_categorical_dtype,
-    is_float_dtype, is_numeric_dtype,
-    is_sparse,
-    _get_dtype)
 from pandas.core.dtypes.cast import maybe_promote
+from pandas.core.dtypes.common import (
+    _get_dtype, is_categorical_dtype, is_datetime64_dtype, is_datetimetz,
+    is_float_dtype, is_numeric_dtype, is_sparse, is_timedelta64_dtype)
 import pandas.core.dtypes.concat as _concat
+from pandas.core.dtypes.missing import isna
 
 import pandas.core.algorithms as algos
 
diff --git a/pandas/core/internals/managers.py b/pandas/core/internals/managers.py
index 0519c5e5abe33..c3762d9819153 100644
--- a/pandas/core/internals/managers.py
+++ b/pandas/core/internals/managers.py
@@ -7,42 +7,34 @@
 
 import numpy as np
 
-from pandas._libs import lib, internals as libinternals
-
+from pandas._libs import internals as libinternals, lib
+from pandas.compat import map, range, zip
 from pandas.util._validators import validate_bool_kwarg
-from pandas.compat import range, map, zip
 
-from pandas.core.dtypes.common import (
-    _NS_DTYPE,
-    is_datetimelike_v_numeric,
-    is_numeric_v_string_like, is_extension_type,
-    is_extension_array_dtype,
-    is_scalar)
 from pandas.core.dtypes.cast import (
-    maybe_promote,
-    infer_dtype_from_scalar,
-    find_common_type,
-    maybe_convert_objects)
-from pandas.core.dtypes.missing import isna
+    find_common_type, infer_dtype_from_scalar, maybe_convert_objects,
+    maybe_promote)
+from pandas.core.dtypes.common import (
+    _NS_DTYPE, is_datetimelike_v_numeric, is_extension_array_dtype,
+    is_extension_type, is_numeric_v_string_like, is_scalar)
 import pandas.core.dtypes.concat as _concat
-from pandas.core.dtypes.generic import ABCSeries, ABCExtensionArray
+from pandas.core.dtypes.generic import ABCExtensionArray, ABCSeries
+from pandas.core.dtypes.missing import isna
 
-from pandas.core.base import PandasObject
 import pandas.core.algorithms as algos
 from pandas.core.arrays.sparse import _maybe_to_sparse
-
+from pandas.core.base import PandasObject
 from pandas.core.index import Index, MultiIndex, ensure_index
 from pandas.core.indexing import maybe_convert_indices
 
 from pandas.io.formats.printing import pprint_thing
 
 from .blocks import (
-    Block, DatetimeTZBlock, CategoricalBlock, ExtensionBlock,
-    _extend_blocks, _merge_blocks, _safe_reshape,
-    make_block, get_block_type)
+    Block, CategoricalBlock, DatetimeTZBlock, ExtensionBlock, _extend_blocks,
+    _merge_blocks, _safe_reshape, get_block_type, make_block)
 from .concat import (  # all for concatenate_block_managers
-    concatenate_join_units, is_uniform_join_units,
-    get_mgr_concatenation_plan, combine_concat_plans)
+    combine_concat_plans, concatenate_join_units, get_mgr_concatenation_plan,
+    is_uniform_join_units)
 
 # TODO: flexible with index=None and/or items=None
 
diff --git a/pandas/core/sparse/api.py b/pandas/core/sparse/api.py
index e3be241bcdd70..33e8b921905ba 100644
--- a/pandas/core/sparse/api.py
+++ b/pandas/core/sparse/api.py
@@ -1,5 +1,5 @@
 # pylint: disable=W0611
 # flake8: noqa
 from pandas.core.arrays.sparse import SparseArray, SparseDtype
-from pandas.core.sparse.series import SparseSeries
 from pandas.core.sparse.frame import SparseDataFrame
+from pandas.core.sparse.series import SparseSeries
diff --git a/pandas/core/sparse/frame.py b/pandas/core/sparse/frame.py
index ee7de49bc1bce..a25ffa2744cb7 100644
--- a/pandas/core/sparse/frame.py
+++ b/pandas/core/sparse/frame.py
@@ -3,32 +3,36 @@
 with float64 data
 """
 from __future__ import division
-# pylint: disable=E1101,E1103,W0231,E0202
 
 import warnings
-from pandas.compat import lmap
-from pandas import compat
+
 import numpy as np
 
-from pandas.core.dtypes.missing import isna, notna
-from pandas.core.dtypes.cast import maybe_upcast, find_common_type
+from pandas._libs.sparse import BlockIndex, get_blocks
+import pandas.compat as compat
+from pandas.compat import lmap
+from pandas.compat.numpy import function as nv
+from pandas.util._decorators import Appender
+
+from pandas.core.dtypes.cast import find_common_type, maybe_upcast
 from pandas.core.dtypes.common import ensure_platform_int, is_scipy_sparse
+from pandas.core.dtypes.missing import isna, notna
 
-from pandas.compat.numpy import function as nv
-from pandas.core.index import Index, MultiIndex, ensure_index
-from pandas.core.series import Series
-from pandas.core.frame import DataFrame, extract_index, _prep_ndarray
 import pandas.core.algorithms as algos
-from pandas.core.internals import (BlockManager,
-                                   create_block_manager_from_arrays)
-import pandas.core.generic as generic
 from pandas.core.arrays.sparse import SparseArray, SparseDtype
-from pandas.core.sparse.series import SparseSeries
-from pandas._libs.sparse import BlockIndex, get_blocks
-from pandas.util._decorators import Appender
-import pandas.core.ops as ops
 import pandas.core.common as com
+from pandas.core.frame import DataFrame, _prep_ndarray, extract_index
+import pandas.core.generic as generic
+from pandas.core.index import Index, MultiIndex, ensure_index
 import pandas.core.indexes.base as ibase
+from pandas.core.internals import (
+    BlockManager, create_block_manager_from_arrays)
+import pandas.core.ops as ops
+from pandas.core.series import Series
+from pandas.core.sparse.series import SparseSeries
+
+# pylint: disable=E1101,E1103,W0231,E0202
+
 
 _shared_doc_kwargs = dict(klass='SparseDataFrame')
 
diff --git a/pandas/core/sparse/scipy_sparse.py b/pandas/core/sparse/scipy_sparse.py
index 748a52f484893..ab4fdeb05f8f1 100644
--- a/pandas/core/sparse/scipy_sparse.py
+++ b/pandas/core/sparse/scipy_sparse.py
@@ -3,10 +3,11 @@
 
 Currently only includes SparseSeries.to_coo helpers.
 """
-from pandas.core.index import MultiIndex, Index
-from pandas.core.series import Series
 from pandas.compat import OrderedDict, lmap
 
+from pandas.core.index import Index, MultiIndex
+from pandas.core.series import Series
+
 
 def _check_is_partition(parts, whole):
     whole = set(whole)
diff --git a/pandas/core/sparse/series.py b/pandas/core/sparse/series.py
index ff32712f9056a..4ea4531c53c72 100644
--- a/pandas/core/sparse/series.py
+++ b/pandas/core/sparse/series.py
@@ -5,36 +5,30 @@
 
 # pylint: disable=E1101,E1103,W0231
 
-import numpy as np
 import warnings
 
-from pandas.core.dtypes.common import (
-    is_scalar,
-)
-from pandas.core.dtypes.missing import isna, notna, is_integer
+import numpy as np
 
-from pandas import compat
-from pandas.compat.numpy import function as nv
-from pandas.core.index import Index
-from pandas.core.series import Series
-from pandas.core.dtypes.generic import ABCSeries, ABCSparseSeries
-from pandas.core.internals import SingleBlockManager
-from pandas.core import generic
-import pandas.core.ops as ops
 import pandas._libs.index as libindex
+import pandas._libs.sparse as splib
+from pandas._libs.sparse import BlockIndex, IntIndex
+import pandas.compat as compat
+from pandas.compat.numpy import function as nv
 from pandas.util._decorators import Appender, Substitution
 
-from pandas.core.arrays import (
-    SparseArray,
-)
-from pandas.core.arrays.sparse import SparseAccessor
-from pandas._libs.sparse import BlockIndex, IntIndex
-import pandas._libs.sparse as splib
+from pandas.core.dtypes.common import is_scalar
+from pandas.core.dtypes.generic import ABCSeries, ABCSparseSeries
+from pandas.core.dtypes.missing import is_integer, isna, notna
 
+from pandas.core import generic
+from pandas.core.arrays import SparseArray
+from pandas.core.arrays.sparse import SparseAccessor
+from pandas.core.index import Index
+from pandas.core.internals import SingleBlockManager
+import pandas.core.ops as ops
+from pandas.core.series import Series
 from pandas.core.sparse.scipy_sparse import (
-    _sparse_series_to_coo,
-    _coo_to_sparse_series)
-
+    _coo_to_sparse_series, _sparse_series_to_coo)
 
 _shared_doc_kwargs = dict(axes='index', klass='SparseSeries',
                           axes_single_arg="{0, 'index'}",
diff --git a/pandas/core/tools/datetimes.py b/pandas/core/tools/datetimes.py
index 0eb2ffeab28f1..2c6fdb3eaf03c 100644
--- a/pandas/core/tools/datetimes.py
+++ b/pandas/core/tools/datetimes.py
@@ -1,36 +1,24 @@
-from functools import partial
-from datetime import datetime, time
 from collections import MutableMapping
+from datetime import datetime, time
+from functools import partial
 
 import numpy as np
 
 from pandas._libs import tslib, tslibs
-from pandas._libs.tslibs.strptime import array_strptime
-from pandas._libs.tslibs import parsing, conversion, Timestamp
+from pandas._libs.tslibs import Timestamp, conversion, parsing
 from pandas._libs.tslibs.parsing import (  # noqa
-    parse_time_string,
-    DateParseError,
-    _format_is_iso,
-    _guess_datetime_format)
+    DateParseError, _format_is_iso, _guess_datetime_format, parse_time_string)
+from pandas._libs.tslibs.strptime import array_strptime
+from pandas.compat import zip
 
 from pandas.core.dtypes.common import (
-    ensure_object,
-    is_datetime64_ns_dtype,
-    is_datetime64_dtype,
-    is_datetime64tz_dtype,
-    is_integer_dtype,
-    is_integer,
-    is_float,
-    is_list_like,
-    is_scalar,
-    is_numeric_dtype,
-    is_object_dtype)
-from pandas.core.dtypes.generic import (
-    ABCIndexClass, ABCSeries,
-    ABCDataFrame)
+    ensure_object, is_datetime64_dtype, is_datetime64_ns_dtype,
+    is_datetime64tz_dtype, is_float, is_integer, is_integer_dtype,
+    is_list_like, is_numeric_dtype, is_object_dtype, is_scalar)
+from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
 from pandas.core.dtypes.missing import notna
+
 from pandas.core import algorithms
-from pandas.compat import zip
 
 
 def _guess_datetime_format_for_array(arr, **kwargs):
diff --git a/pandas/core/tools/numeric.py b/pandas/core/tools/numeric.py
index 12699927141cb..1d4973de92b99 100644
--- a/pandas/core/tools/numeric.py
+++ b/pandas/core/tools/numeric.py
@@ -1,16 +1,15 @@
 import numpy as np
-import pandas as pd
-from pandas.core.dtypes.common import (
-    is_scalar,
-    is_numeric_dtype,
-    is_decimal,
-    is_datetime_or_timedelta_dtype,
-    is_number,
-    ensure_object)
-from pandas.core.dtypes.generic import ABCSeries, ABCIndexClass
-from pandas.core.dtypes.cast import maybe_downcast_to_dtype
+
 from pandas._libs import lib
 
+from pandas.core.dtypes.cast import maybe_downcast_to_dtype
+from pandas.core.dtypes.common import (
+    ensure_object, is_datetime_or_timedelta_dtype, is_decimal, is_number,
+    is_numeric_dtype, is_scalar)
+from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
+
+import pandas as pd
+
 
 def to_numeric(arg, errors='raise', downcast=None):
     """
diff --git a/pandas/core/tools/timedeltas.py b/pandas/core/tools/timedeltas.py
index db93820c6942f..2579efdbc65fe 100644
--- a/pandas/core/tools/timedeltas.py
+++ b/pandas/core/tools/timedeltas.py
@@ -3,14 +3,15 @@
 """
 
 import numpy as np
-import pandas as pd
+
 from pandas._libs import tslibs
-from pandas._libs.tslibs.timedeltas import (convert_to_timedelta64,
-                                            parse_timedelta_unit)
+from pandas._libs.tslibs.timedeltas import (
+    convert_to_timedelta64, parse_timedelta_unit)
 
 from pandas.core.dtypes.common import is_list_like
-from pandas.core.dtypes.generic import ABCSeries, ABCIndexClass
+from pandas.core.dtypes.generic import ABCIndexClass, ABCSeries
 
+import pandas as pd
 from pandas.core.arrays.timedeltas import sequence_to_td64ns
 
 
diff --git a/pandas/core/util/hashing.py b/pandas/core/util/hashing.py
index 6a2cfd4d4a7b3..0e58b69465d3c 100644
--- a/pandas/core/util/hashing.py
+++ b/pandas/core/util/hashing.py
@@ -2,18 +2,17 @@
 data hash pandas / numpy objects
 """
 import itertools
+
 import numpy as np
+
 from pandas._libs import hashing, tslibs
-from pandas.core.dtypes.generic import (
-    ABCMultiIndex,
-    ABCIndexClass,
-    ABCSeries,
-    ABCDataFrame)
+
+from pandas.core.dtypes.cast import infer_dtype_from_scalar
 from pandas.core.dtypes.common import (
-    is_categorical_dtype, is_list_like, is_extension_array_dtype)
+    is_categorical_dtype, is_extension_array_dtype, is_list_like)
+from pandas.core.dtypes.generic import (
+    ABCDataFrame, ABCIndexClass, ABCMultiIndex, ABCSeries)
 from pandas.core.dtypes.missing import isna
-from pandas.core.dtypes.cast import infer_dtype_from_scalar
-
 
 # 16 byte long hashing key
 _default_hash_key = '0123456789123456'
diff --git a/setup.cfg b/setup.cfg
index 5132e6c5f79cd..0214922585077 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -138,25 +138,6 @@ skip=
     pandas/core/indexes/accessors.py,
     pandas/core/indexes/period.py,
     pandas/core/indexes/frozen.py,
-    pandas/core/arrays/categorical.py,
-    pandas/core/arrays/integer.py,
-    pandas/core/arrays/interval.py,
-    pandas/core/arrays/timedeltas.py,
-    pandas/core/arrays/datetimelike.py,
-    pandas/core/arrays/datetimes.py,
-    pandas/core/arrays/base.py,
-    pandas/core/arrays/period.py,
-    pandas/core/util/hashing.py,
-    pandas/core/tools/numeric.py,
-    pandas/core/tools/timedeltas.py,
-    pandas/core/tools/datetimes.py,
-    pandas/core/internals/concat.py,
-    pandas/core/internals/managers.py,
-    pandas/core/internals/blocks.py,
-    pandas/core/sparse/api.py,
-    pandas/core/sparse/series.py,
-    pandas/core/sparse/frame.py,
-    pandas/core/sparse/scipy_sparse.py,
     pandas/tests/test_errors.py,
     pandas/tests/test_base.py,
     pandas/tests/test_register_accessor.py,