Base classes in Python 3 don't need to subclass object (pydata#2950)

* Base classes in Python 3 don't need to subclass object

* What's new

asv_bench/benchmarks/dataset_io.py

@@ -19,7 +19,7 @@
 os.environ['HDF5_USE_FILE_LOCKING'] = 'FALSE'
 
 
-class IOSingleNetCDF(object):
+class IOSingleNetCDF:
     """
     A few examples that benchmark reading/writing a single netCDF file with
     xarray
@@ -214,7 +214,7 @@ def time_load_dataset_scipy_with_time_chunks(self):
                             chunks=self.time_chunks).load()
 
 
-class IOMultipleNetCDF(object):
+class IOMultipleNetCDF:
     """
     A few examples that benchmark reading/writing multiple netCDF files with
     xarray
@@ -419,7 +419,7 @@ def create_delayed_write():
     return ds.to_netcdf('file.nc', engine='netcdf4', compute=False)
 
 
-class IOWriteNetCDFDask(object):
+class IOWriteNetCDFDask:
     timeout = 60
     repeat = 1
     number = 5
@@ -432,7 +432,7 @@ def time_write(self):
         self.write.compute()
 
 
-class IOWriteNetCDFDaskDistributed(object):
+class IOWriteNetCDFDaskDistributed:
     def setup(self):
         try:
             import distributed

asv_bench/benchmarks/indexing.py

@@ -58,7 +58,7 @@
 }
 
 
-class Base(object):
+class Base:
     def setup(self, key):
         self.ds = xr.Dataset(
             {'var1': (('x', 'y'), randn((nx, ny), frac_nan=0.1)),

asv_bench/benchmarks/interp.py

@@ -24,7 +24,7 @@
 new_y_long = np.linspace(0.1, 0.9, 1000)
 
 
-class Interpolation(object):
+class Interpolation:
     def setup(self, *args, **kwargs):
         self.ds = xr.Dataset(
             {'var1': (('x', 'y'), randn_xy),

asv_bench/benchmarks/reindexing.py

@@ -7,7 +7,7 @@
 from . import requires_dask
 
 
-class Reindex(object):
+class Reindex:
     def setup(self):
         data = np.random.RandomState(0).randn(1000, 100, 100)
         self.ds = xr.Dataset({'temperature': (('time', 'x', 'y'), data)},

asv_bench/benchmarks/rolling.py

@@ -19,7 +19,7 @@
 randn_long = randn((long_nx, ), frac_nan=0.1)
 
 
-class Rolling(object):
+class Rolling:
     def setup(self, *args, **kwargs):
         self.ds = xr.Dataset(
             {'var1': (('x', 'y'), randn_xy),

asv_bench/benchmarks/unstacking.py

@@ -7,7 +7,7 @@
 from . import requires_dask
 
 
-class Unstacking(object):
+class Unstacking:
     def setup(self):
         data = np.random.RandomState(0).randn(1, 1000, 500)
         self.ds = xr.DataArray(data).stack(flat_dim=['dim_1', 'dim_2'])

doc/contributing.rst

@@ -457,7 +457,7 @@ typically find tests wrapped in a class.
 
 .. code-block:: python
 
-    class TestReallyCoolFeature(object):
+    class TestReallyCoolFeature:
         ....
 
 Going forward, we are moving to a more *functional* style using the

doc/examples/_code/accessor_example.py

@@ -2,7 +2,7 @@
 
 
 @xr.register_dataset_accessor('geo')
-class GeoAccessor(object):
+class GeoAccessor:
     def __init__(self, xarray_obj):
         self._obj = xarray_obj
         self._center = None

doc/whats-new.rst

@@ -27,7 +27,9 @@ Enhancements
 - Character arrays' character dimension name decoding and encoding handled by
   ``var.encoding['char_dim_name']`` (:issue:`2895`)
   By `James McCreight <https://github.com/jmccreight>`_.
-
+- Clean up Python 2 compatibility in code (:issue:`2950`)
+  By `Guido Imperiale <https://github.com/crusaderky>`_.
+
 Bug fixes
 ~~~~~~~~~
 

xarray/backends/api.py

@@ -529,7 +529,7 @@ def open_dataarray(filename_or_obj, group=None, decode_cf=True,
     return data_array
 
 
-class _MultiFileCloser(object):
+class _MultiFileCloser:
     def __init__(self, file_objs):
         self.file_objs = file_objs
 

xarray/backends/common.py

@@ -154,7 +154,7 @@ def __exit__(self, exception_type, exception_value, traceback):
         self.close()
 
 
-class ArrayWriter(object):
+class ArrayWriter:
     def __init__(self, lock=None):
         self.sources = []
         self.targets = []

xarray/backends/file_manager.py

@@ -19,7 +19,7 @@
 _DEFAULT_MODE = utils.ReprObject('<unused>')
 
 
-class FileManager(object):
+class FileManager:
     """Manager for acquiring and closing a file object.
 
     Use FileManager subclasses (CachingFileManager in particular) on backend
@@ -237,7 +237,7 @@ def __repr__(self):
             type(self).__name__, self._opener, args_string, self._kwargs)
 
 
-class _RefCounter(object):
+class _RefCounter:
     """Class for keeping track of reference counts."""
     def __init__(self, counts):
         self._counts = counts

xarray/backends/locks.py

@@ -135,7 +135,7 @@ def acquire(lock, blocking=True):
         return lock.acquire(blocking)
 
 
-class CombinedLock(object):
+class CombinedLock:
     """A combination of multiple locks.
 
     Like a locked door, a CombinedLock is locked if any of its constituent
@@ -167,7 +167,7 @@ def __repr__(self):
         return "CombinedLock(%r)" % list(self.locks)
 
 
-class DummyLock(object):
+class DummyLock:
     """DummyLock provides the lock API without any actual locking."""
 
     def acquire(self, blocking=True):

xarray/backends/netCDF4_.py

@@ -228,7 +228,7 @@ def _extract_nc4_variable_encoding(variable, raise_on_invalid=False,
     return encoding
 
 
-class GroupWrapper(object):
+class GroupWrapper:
     """Wrap netCDF4.Group objects so closing them closes the root group."""
     def __init__(self, value):
         self.value = value

xarray/coding/cftime_offsets.py

@@ -77,7 +77,7 @@ def get_date_type(calendar):
         return calendars[calendar]
 
 
-class BaseCFTimeOffset(object):
+class BaseCFTimeOffset:
     _freq = None  # type: ClassVar[str]
     _day_option = None  # type: ClassVar[str]
 

xarray/coding/variables.py

@@ -15,7 +15,7 @@ class SerializationWarning(RuntimeWarning):
     """Warnings about encoding/decoding issues in serialization."""
 
 
-class VariableCoder(object):
+class VariableCoder:
     """Base class for encoding and decoding transformations on variables.
 
     We use coders for transforming variables between xarray's data model and

xarray/core/accessors.py

@@ -110,7 +110,7 @@ def _round_field(values, name, freq):
         return _round_series(values, name, freq)
 
 
-class DatetimeAccessor(object):
+class DatetimeAccessor:
     """Access datetime fields for DataArrays with datetime-like dtypes.
 
      Similar to pandas, fields can be accessed through the `.dt` attribute

xarray/core/arithmetic.py

@@ -8,7 +8,7 @@
 from .utils import not_implemented
 
 
-class SupportsArithmetic(object):
+class SupportsArithmetic:
     """Base class for xarray types that support arithmetic.
 
     Used by Dataset, DataArray, Variable and GroupBy.

xarray/core/computation.py

@@ -29,7 +29,7 @@
 _JOINS_WITHOUT_FILL_VALUES = frozenset({'inner', 'exact'})
 
 
-class _UFuncSignature(object):
+class _UFuncSignature:
     """Core dimensions signature for a given function.
 
     Based on the signature provided by generalized ufuncs in NumPy.

xarray/core/coordinates.py

@@ -258,7 +258,7 @@ def _ipython_key_completions_(self):
         return self._data._ipython_key_completions_()
 
 
-class LevelCoordinatesSource(object):
+class LevelCoordinatesSource:
     """Iterator for MultiIndex level coordinates.
 
     Used for attribute style lookup with AttrAccessMixin. Not returned directly

xarray/core/dataarray.py

@@ -92,7 +92,7 @@ def _infer_coords_and_dims(shape, coords, dims):
     return new_coords, dims
 
 
-class _LocIndexer(object):
+class _LocIndexer:
     def __init__(self, data_array):
         self.data_array = data_array
 

xarray/core/dataset.py

@@ -303,7 +303,7 @@ def _ipython_key_completions_(self):
                 if key not in self._dataset._coord_names]
 
 
-class _LocIndexer(object):
+class _LocIndexer:
     def __init__(self, dataset):
         self.dataset = dataset
 

xarray/core/dtypes.py

@@ -9,7 +9,7 @@
 
 
 @functools.total_ordering
-class AlwaysGreaterThan(object):
+class AlwaysGreaterThan:
     def __gt__(self, other):
         return True
 
@@ -18,7 +18,7 @@ def __eq__(self, other):
 
 
 @functools.total_ordering
-class AlwaysLessThan(object):
+class AlwaysLessThan:
     def __lt__(self, other):
         return True
 

xarray/core/extensions.py

@@ -8,7 +8,7 @@ class AccessorRegistrationWarning(Warning):
     """Warning for conflicts in accessor registration."""
 
 
-class _CachedAccessor(object):
+class _CachedAccessor:
     """Custom property-like object (descriptor) for caching accessors."""
 
     def __init__(self, name, accessor):
@@ -81,7 +81,7 @@ def register_dataset_accessor(name):
         import xarray as xr
 
         @xr.register_dataset_accessor('geo')
-        class GeoAccessor(object):
+        class GeoAccessor:
             def __init__(self, xarray_obj):
                 self._obj = xarray_obj
 

xarray/core/groupby.py

@@ -113,7 +113,7 @@ def _inverse_permutation_indices(positions):
     return indices
 
 
-class _DummyGroup(object):
+class _DummyGroup:
     """Class for keeping track of grouped dimensions without coordinates.
 
     Should not be user visible.

xarray/core/indexing.py

@@ -294,7 +294,7 @@ def _index_indexer_1d(old_indexer, applied_indexer, size):
     return indexer
 
 
-class ExplicitIndexer(object):
+class ExplicitIndexer:
     """Base class for explicit indexer objects.
 
     ExplicitIndexer objects wrap a tuple of values given by their ``tuple``
@@ -430,7 +430,7 @@ def __init__(self, key):
         super(VectorizedIndexer, self).__init__(new_key)
 
 
-class ExplicitlyIndexed(object):
+class ExplicitlyIndexed:
     """Mixin to mark support for Indexer subclasses in indexing."""
 
 
@@ -740,7 +740,7 @@ def _combine_indexers(old_key, shape, new_key):
                                    np.broadcast_arrays(*old_key.tuple)))
 
 
-class IndexingSupport(object):  # could inherit from enum.Enum on Python 3
+class IndexingSupport:  # could inherit from enum.Enum on Python 3
     # for backends that support only basic indexer
     BASIC = 'BASIC'
     # for backends that support basic / outer indexer

xarray/core/missing.py

@@ -14,7 +14,7 @@
 from .variable import Variable, broadcast_variables
 
 
-class BaseInterpolator(object):
+class BaseInterpolator:
     '''gerneric interpolator class for normalizing interpolation methods'''
     cons_kwargs = {}  # type: Dict[str, Any]
     call_kwargs = {}  # type: Dict[str, Any]

xarray/core/nputils.py

@@ -120,7 +120,7 @@ def _advanced_indexer_subspaces(key):
     return mixed_positions, vindex_positions
 
 
-class NumpyVIndexAdapter(object):
+class NumpyVIndexAdapter:
     """Object that implements indexing like vindex on a np.ndarray.
 
     This is a pure Python implementation of (some of) the logic in this NumPy

xarray/core/options.py

@@ -69,7 +69,7 @@ def _get_keep_attrs(default):
             " True, False or 'default'.")
 
 
-class set_options(object):
+class set_options:
     """Set options for xarray in a controlled context.
 
     Currently supported options:

xarray/core/resample.py

@@ -4,7 +4,7 @@
 RESAMPLE_DIM = '__resample_dim__'
 
 
-class Resample(object):
+class Resample:
     """An object that extends the `GroupBy` object with additional logic
     for handling specialized re-sampling operations.
 

xarray/core/resample_cftime.py

@@ -45,7 +45,7 @@
 import pandas as pd
 
 
-class CFTimeGrouper(object):
+class CFTimeGrouper:
     """This is a simple container for the grouping parameters that implements a
     single method, the only one required for resampling in xarray.  It cannot
     be used in a call to groupby like a pandas.Grouper object can."""

xarray/core/rolling.py

@@ -12,7 +12,7 @@
 from .pycompat import dask_array_type
 
 
-class Rolling(object):
+class Rolling:
     """A object that implements the moving window pattern.
 
     See Also
@@ -435,7 +435,7 @@ def construct(self, window_dim, stride=1, fill_value=dtypes.NA):
             **{self.dim: slice(None, None, stride)})
 
 
-class Coarsen(object):
+class Coarsen:
     """A object that implements the coarsen.
 
     See Also

xarray/plot/facetgrid.py

@@ -30,7 +30,7 @@ def _nicetitle(coord, value, maxchar, template):
     return title
 
 
-class FacetGrid(object):
+class FacetGrid:
     """
     Initialize the matplotlib figure and FacetGrid object.
 

xarray/plot/plot.py

@@ -410,7 +410,7 @@ def hist(darray, figsize=None, size=None, aspect=None, ax=None, **kwargs):
 
 # MUST run before any 2d plotting functions are defined since
 # _plot2d decorator adds them as methods here.
-class _PlotMethods(object):
+class _PlotMethods:
     """
     Enables use of xarray.plot functions as attributes on a DataArray.
     For example, DataArray.plot.imshow