diff --git a/pandas/core/algorithms.py b/pandas/core/algorithms.py
index 9ff8ba7bb23d2..ecdad8752113a 100644
--- a/pandas/core/algorithms.py
+++ b/pandas/core/algorithms.py
@@ -3,40 +3,31 @@
 intended for public consumption
 """
 from __future__ import division
-from warnings import warn, catch_warnings, simplefilter
+
 from textwrap import dedent
+from warnings import catch_warnings, simplefilter, warn
 
 import numpy as np
 
+from pandas._libs import algos, hashtable as htable, lib
+from pandas._libs.tslib import iNaT
+from pandas.util._decorators import Appender, Substitution, deprecate_kwarg
+
 from pandas.core.dtypes.cast import (
-    maybe_promote, construct_1d_object_array_from_listlike)
-from pandas.core.dtypes.generic import (
-    ABCSeries, ABCIndex,
-    ABCIndexClass)
+    construct_1d_object_array_from_listlike, maybe_promote)
 from pandas.core.dtypes.common import (
-    is_array_like,
-    is_unsigned_integer_dtype, is_signed_integer_dtype,
-    is_integer_dtype, is_complex_dtype,
-    is_object_dtype,
-    is_extension_array_dtype,
-    is_categorical_dtype, is_sparse,
-    is_period_dtype,
-    is_numeric_dtype, is_float_dtype,
-    is_bool_dtype, needs_i8_conversion,
-    is_datetimetz,
-    is_datetime64_any_dtype, is_datetime64tz_dtype,
-    is_timedelta64_dtype, is_datetimelike,
-    is_interval_dtype, is_scalar, is_list_like,
-    ensure_platform_int, ensure_object,
-    ensure_float64, ensure_uint64,
-    ensure_int64)
+    ensure_float64, ensure_int64, ensure_object, ensure_platform_int,
+    ensure_uint64, is_array_like, is_bool_dtype, is_categorical_dtype,
+    is_complex_dtype, is_datetime64_any_dtype, is_datetime64tz_dtype,
+    is_datetimelike, is_datetimetz, is_extension_array_dtype, is_float_dtype,
+    is_integer_dtype, is_interval_dtype, is_list_like, is_numeric_dtype,
+    is_object_dtype, is_period_dtype, is_scalar, is_signed_integer_dtype,
+    is_sparse, is_timedelta64_dtype, is_unsigned_integer_dtype,
+    needs_i8_conversion)
+from pandas.core.dtypes.generic import ABCIndex, ABCIndexClass, ABCSeries
 from pandas.core.dtypes.missing import isna, na_value_for_dtype
 
 from pandas.core import common as com
-from pandas._libs import algos, lib, hashtable as htable
-from pandas._libs.tslib import iNaT
-from pandas.util._decorators import (Appender, Substitution,
-                                     deprecate_kwarg)
 
 _shared_docs = {}
 
diff --git a/pandas/core/apply.py b/pandas/core/apply.py
index 40cd952a62138..c44e64d29ed26 100644
--- a/pandas/core/apply.py
+++ b/pandas/core/apply.py
@@ -1,15 +1,15 @@
 import warnings
+
 import numpy as np
-from pandas import compat
+
 from pandas._libs import reduction
-from pandas.core.dtypes.generic import ABCSeries
-from pandas.core.dtypes.common import (
-    is_extension_type,
-    is_dict_like,
-    is_list_like,
-    is_sequence)
+import pandas.compat as compat
 from pandas.util._decorators import cache_readonly
 
+from pandas.core.dtypes.common import (
+    is_dict_like, is_extension_type, is_list_like, is_sequence)
+from pandas.core.dtypes.generic import ABCSeries
+
 from pandas.io.formats.printing import pprint_thing
 
 
diff --git a/pandas/core/base.py b/pandas/core/base.py
index 9dc4237bdcd2d..fd303182959a5 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -1,32 +1,28 @@
 """
 Base and utility classes for pandas objects.
 """
-import warnings
 import textwrap
-from pandas import compat
-from pandas.compat import builtins
-import numpy as np
+import warnings
 
-from pandas.core.dtypes.missing import isna
-from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries, ABCIndexClass
-from pandas.core.dtypes.common import (
-    is_datetimelike,
-    is_object_dtype,
-    is_list_like,
-    is_scalar,
-    is_extension_type,
-    is_extension_array_dtype)
+import numpy as np
 
-from pandas.util._validators import validate_bool_kwarg
-from pandas.errors import AbstractMethodError
-from pandas.core import common as com, algorithms
-import pandas.core.nanops as nanops
 import pandas._libs.lib as lib
+import pandas.compat as compat
+from pandas.compat import PYPY, OrderedDict, builtins
 from pandas.compat.numpy import function as nv
-from pandas.compat import PYPY, OrderedDict
-from pandas.util._decorators import Appender, cache_readonly, Substitution
+from pandas.errors import AbstractMethodError
+from pandas.util._decorators import Appender, Substitution, cache_readonly
+from pandas.util._validators import validate_bool_kwarg
 
+from pandas.core.dtypes.common import (
+    is_datetimelike, is_extension_array_dtype, is_extension_type, is_list_like,
+    is_object_dtype, is_scalar)
+from pandas.core.dtypes.generic import ABCDataFrame, ABCIndexClass, ABCSeries
+from pandas.core.dtypes.missing import isna
+
+from pandas.core import algorithms, common as com
 from pandas.core.accessor import DirNamesMixin
+import pandas.core.nanops as nanops
 
 _shared_docs = dict()
 _indexops_doc_kwargs = dict(klass='IndexOpsMixin', inplace='',
diff --git a/pandas/core/categorical.py b/pandas/core/categorical.py
index 530a3ecb5f378..43c35c4000bb6 100644
--- a/pandas/core/categorical.py
+++ b/pandas/core/categorical.py
@@ -1,8 +1,9 @@
 import warnings
 
+from pandas.core.dtypes.dtypes import CategoricalDtype  # noqa
+
+from pandas.core.arrays import Categorical  # noqa
+
 # TODO: Remove after 0.23.x
 warnings.warn("'pandas.core' is private. Use 'pandas.Categorical'",
               FutureWarning, stacklevel=2)
-
-from pandas.core.arrays import Categorical  # noqa
-from pandas.core.dtypes.dtypes import CategoricalDtype  # noqa
diff --git a/pandas/core/common.py b/pandas/core/common.py
index 0a82dd8636888..b4de0daa13b16 100644
--- a/pandas/core/common.py
+++ b/pandas/core/common.py
@@ -4,25 +4,23 @@
 Note: pandas.core.common is *not* part of the public API.
 """
 
+import collections
 from datetime import datetime, timedelta
 from functools import partial
 import inspect
-import collections
 
 import numpy as np
+
 from pandas._libs import lib, tslibs
+import pandas.compat as compat
+from pandas.compat import PY36, OrderedDict, iteritems
 
-from pandas import compat
-from pandas.compat import iteritems, PY36, OrderedDict
-from pandas.core.dtypes.generic import (
-    ABCSeries, ABCIndex, ABCIndexClass
-)
+from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
 from pandas.core.dtypes.common import (
-    is_integer, is_bool_dtype, is_extension_array_dtype, is_array_like
-)
+    is_array_like, is_bool_dtype, is_extension_array_dtype, is_integer)
+from pandas.core.dtypes.generic import ABCIndex, ABCIndexClass, ABCSeries
 from pandas.core.dtypes.inference import _iterable_not_string
 from pandas.core.dtypes.missing import isna, isnull, notnull  # noqa
-from pandas.core.dtypes.cast import construct_1d_object_array_from_listlike
 
 
 class SettingWithCopyError(ValueError):
diff --git a/pandas/core/config.py b/pandas/core/config.py
index f178600b74626..f4757bfd8069c 100644
--- a/pandas/core/config.py
+++ b/pandas/core/config.py
@@ -48,13 +48,13 @@
 
 """
 
-import re
-
 from collections import namedtuple
 from contextlib import contextmanager
+import re
 import warnings
-from pandas.compat import map, lmap, u
+
 import pandas.compat as compat
+from pandas.compat import lmap, map, u
 
 DeprecatedOption = namedtuple('DeprecatedOption', 'key msg rkey removal_ver')
 RegisteredOption = namedtuple('RegisteredOption',
diff --git a/pandas/core/config_init.py b/pandas/core/config_init.py
index b836a35b8cf29..d42a1ab72b156 100644
--- a/pandas/core/config_init.py
+++ b/pandas/core/config_init.py
@@ -10,8 +10,10 @@
 
 """
 import pandas.core.config as cf
-from pandas.core.config import (is_int, is_bool, is_text, is_instance_factory,
-                                is_one_of_factory, is_callable)
+from pandas.core.config import (
+    is_bool, is_callable, is_instance_factory, is_int, is_one_of_factory,
+    is_text)
+
 from pandas.io.formats.console import detect_console_encoding
 from pandas.io.formats.terminal import is_terminal
 
diff --git a/pandas/core/generic.py b/pandas/core/generic.py
index 5bb364e1d1605..9f6addb74f8da 100644
--- a/pandas/core/generic.py
+++ b/pandas/core/generic.py
@@ -1,64 +1,52 @@
 # pylint: disable=W0231,E1101
 import collections
 import functools
-import warnings
-import operator
-import weakref
 import gc
 import json
+import operator
+import warnings
+import weakref
 
 import numpy as np
-import pandas as pd
 
-from pandas._libs import properties, Timestamp, iNaT
+from pandas._libs import Timestamp, iNaT, properties
+import pandas.compat as compat
+from pandas.compat import (
+    cPickle as pkl, isidentifier, lrange, lzip, map, set_function_name,
+    string_types, to_str, zip)
+from pandas.compat.numpy import function as nv
 from pandas.errors import AbstractMethodError
+from pandas.util._decorators import (
+    Appender, Substitution, rewrite_axis_style_signature)
+from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
 
-from pandas.core.dtypes.common import (
-    ensure_int64,
-    ensure_object,
-    is_scalar,
-    is_number,
-    is_integer, is_bool,
-    is_bool_dtype,
-    is_numeric_dtype,
-    is_datetime64_any_dtype,
-    is_timedelta64_dtype,
-    is_datetime64tz_dtype,
-    is_list_like,
-    is_dict_like,
-    is_re_compilable,
-    is_period_arraylike,
-    is_object_dtype,
-    is_extension_array_dtype,
-    pandas_dtype)
 from pandas.core.dtypes.cast import maybe_promote, maybe_upcast_putmask
+from pandas.core.dtypes.common import (
+    ensure_int64, ensure_object, is_bool, is_bool_dtype,
+    is_datetime64_any_dtype, is_datetime64tz_dtype, is_dict_like,
+    is_extension_array_dtype, is_integer, is_list_like, is_number,
+    is_numeric_dtype, is_object_dtype, is_period_arraylike, is_re_compilable,
+    is_scalar, is_timedelta64_dtype, pandas_dtype)
+from pandas.core.dtypes.generic import ABCDataFrame, ABCPanel, ABCSeries
 from pandas.core.dtypes.inference import is_hashable
 from pandas.core.dtypes.missing import isna, notna
-from pandas.core.dtypes.generic import ABCSeries, ABCPanel, ABCDataFrame
 
+import pandas as pd
+from pandas.core import config, missing, nanops
+import pandas.core.algorithms as algos
 from pandas.core.base import PandasObject, SelectionMixin
-from pandas.core.index import (Index, MultiIndex, ensure_index,
-                               InvalidIndexError, RangeIndex)
-import pandas.core.indexing as indexing
+import pandas.core.common as com
+from pandas.core.index import (
+    Index, InvalidIndexError, MultiIndex, RangeIndex, ensure_index)
 from pandas.core.indexes.datetimes import DatetimeIndex
-from pandas.core.indexes.period import PeriodIndex, Period
+from pandas.core.indexes.period import Period, PeriodIndex
+import pandas.core.indexing as indexing
 from pandas.core.internals import BlockManager
-import pandas.core.algorithms as algos
-import pandas.core.common as com
-import pandas.core.missing as missing
+from pandas.core.ops import _align_method_FRAME
+
+from pandas.io.formats.format import DataFrameFormatter, format_percentiles
 from pandas.io.formats.printing import pprint_thing
-from pandas.io.formats.format import format_percentiles, DataFrameFormatter
 from pandas.tseries.frequencies import to_offset
-from pandas import compat
-from pandas.compat.numpy import function as nv
-from pandas.compat import (map, zip, lzip, lrange, string_types, to_str,
-                           isidentifier, set_function_name, cPickle as pkl)
-from pandas.core.ops import _align_method_FRAME
-import pandas.core.nanops as nanops
-from pandas.util._decorators import (Appender, Substitution,
-                                     rewrite_axis_style_signature)
-from pandas.util._validators import validate_bool_kwarg, validate_fillna_kwargs
-from pandas.core import config
 
 # goal is to be able to define the docs close to function, while still being
 # able to share
diff --git a/pandas/core/indexes/accessors.py b/pandas/core/indexes/accessors.py
index c3b94c297652a..6138f73726e0a 100644
--- a/pandas/core/indexes/accessors.py
+++ b/pandas/core/indexes/accessors.py
@@ -3,20 +3,18 @@
 """
 import numpy as np
 
-from pandas.core.dtypes.generic import ABCSeries
 from pandas.core.dtypes.common import (
-    is_period_arraylike,
-    is_datetime_arraylike, is_integer_dtype,
-    is_datetime64_dtype, is_datetime64tz_dtype,
-    is_timedelta64_dtype, is_categorical_dtype,
-    is_list_like)
+    is_categorical_dtype, is_datetime64_dtype, is_datetime64tz_dtype,
+    is_datetime_arraylike, is_integer_dtype, is_list_like, is_period_arraylike,
+    is_timedelta64_dtype)
+from pandas.core.dtypes.generic import ABCSeries
 
 from pandas.core.accessor import PandasDelegate, delegate_names
+from pandas.core.algorithms import take_1d
 from pandas.core.base import NoNewAttributesMixin, PandasObject
 from pandas.core.indexes.datetimes import DatetimeIndex
 from pandas.core.indexes.period import PeriodArray
 from pandas.core.indexes.timedeltas import TimedeltaIndex
-from pandas.core.algorithms import take_1d
 
 
 class Properties(PandasDelegate, PandasObject, NoNewAttributesMixin):
diff --git a/pandas/core/indexes/api.py b/pandas/core/indexes/api.py
index fb090c0fd83ba..6299fc482d0df 100644
--- a/pandas/core/indexes/api.py
+++ b/pandas/core/indexes/api.py
@@ -1,23 +1,21 @@
 import textwrap
 import warnings
 
-from pandas.core.indexes.base import (Index,
-                                      _new_Index,
-                                      ensure_index,
-                                      ensure_index_from_sequences,
-                                      InvalidIndexError)  # noqa
-from pandas.core.indexes.category import CategoricalIndex  # noqa
-from pandas.core.indexes.multi import MultiIndex  # noqa
-from pandas.core.indexes.interval import IntervalIndex  # noqa
-from pandas.core.indexes.numeric import (NumericIndex, Float64Index,  # noqa
-                                    Int64Index, UInt64Index)
-from pandas.core.indexes.range import RangeIndex  # noqa
-from pandas.core.indexes.timedeltas import TimedeltaIndex
-from pandas.core.indexes.period import PeriodIndex
-from pandas.core.indexes.datetimes import DatetimeIndex
+from pandas._libs import NaT, lib
 
 import pandas.core.common as com
-from pandas._libs import lib, NaT
+from pandas.core.indexes.base import (
+    Index, _new_Index, ensure_index, ensure_index_from_sequences)
+from pandas.core.indexes.base import InvalidIndexError  # noqa:F401
+from pandas.core.indexes.category import CategoricalIndex  # noqa:F401
+from pandas.core.indexes.datetimes import DatetimeIndex
+from pandas.core.indexes.interval import IntervalIndex  # noqa:F401
+from pandas.core.indexes.multi import MultiIndex  # noqa:F401
+from pandas.core.indexes.numeric import (  # noqa:F401
+    Float64Index, Int64Index, NumericIndex, UInt64Index)
+from pandas.core.indexes.period import PeriodIndex
+from pandas.core.indexes.range import RangeIndex  # noqa:F401
+from pandas.core.indexes.timedeltas import TimedeltaIndex
 
 _sort_msg = textwrap.dedent("""\
 Sorting because non-concatenation axis is not aligned. A future version
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 93af7b9933782..29fb541991389 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -1,69 +1,50 @@
 from datetime import datetime, timedelta
-import warnings
 import operator
 from textwrap import dedent
+import warnings
 
 import numpy as np
-from pandas._libs import (lib, index as libindex, tslibs,
-                          algos as libalgos, join as libjoin,
-                          Timedelta)
-from pandas._libs.lib import is_datetime_array
 
-from pandas.compat import range, u, set_function_name
+from pandas._libs import (
+    Timedelta, algos as libalgos, index as libindex, join as libjoin, lib,
+    tslibs)
+from pandas._libs.lib import is_datetime_array
+import pandas.compat as compat
+from pandas.compat import range, set_function_name, u
 from pandas.compat.numpy import function as nv
-from pandas import compat
+from pandas.util._decorators import Appender, Substitution, cache_readonly
 
-from pandas.core.accessor import CachedAccessor
-from pandas.core.arrays import ExtensionArray
-from pandas.core.dtypes.generic import (
-    ABCSeries, ABCDataFrame,
-    ABCMultiIndex,
-    ABCPeriodIndex, ABCTimedeltaIndex, ABCDatetimeIndex,
-    ABCDateOffset, ABCIndexClass, ABCTimedeltaArray)
-from pandas.core.dtypes.missing import isna, array_equivalent
 from pandas.core.dtypes.cast import maybe_cast_to_integer_array
 from pandas.core.dtypes.common import (
-    ensure_int64,
-    ensure_object,
-    ensure_categorical,
-    ensure_platform_int,
-    is_integer,
-    is_float,
-    is_dtype_equal,
-    is_dtype_union_equal,
-    is_object_dtype,
-    is_categorical,
-    is_categorical_dtype,
-    is_interval_dtype,
-    is_period_dtype,
-    is_bool,
-    is_bool_dtype,
-    is_signed_integer_dtype,
-    is_unsigned_integer_dtype,
-    is_integer_dtype, is_float_dtype,
-    is_datetime64_any_dtype,
-    is_datetime64tz_dtype,
-    is_timedelta64_dtype,
-    is_extension_array_dtype,
-    is_hashable,
-    is_iterator, is_list_like,
-    is_scalar)
-
-from pandas.core.base import PandasObject, IndexOpsMixin
-import pandas.core.common as com
+    ensure_categorical, ensure_int64, ensure_object, ensure_platform_int,
+    is_bool, is_bool_dtype, is_categorical, is_categorical_dtype,
+    is_datetime64_any_dtype, is_datetime64tz_dtype, is_dtype_equal,
+    is_dtype_union_equal, is_extension_array_dtype, is_float, is_float_dtype,
+    is_hashable, is_integer, is_integer_dtype, is_interval_dtype, is_iterator,
+    is_list_like, is_object_dtype, is_period_dtype, is_scalar,
+    is_signed_integer_dtype, is_timedelta64_dtype, is_unsigned_integer_dtype)
+import pandas.core.dtypes.concat as _concat
+from pandas.core.dtypes.generic import (
+    ABCDataFrame, ABCDateOffset, ABCDatetimeIndex, ABCIndexClass,
+    ABCMultiIndex, ABCPeriodIndex, ABCSeries, ABCTimedeltaArray,
+    ABCTimedeltaIndex)
+from pandas.core.dtypes.missing import array_equivalent, isna
+
 from pandas.core import ops
-from pandas.util._decorators import (
-    Appender, Substitution, cache_readonly)
+from pandas.core.accessor import CachedAccessor
+import pandas.core.algorithms as algos
+from pandas.core.arrays import ExtensionArray
+from pandas.core.base import IndexOpsMixin, PandasObject
+import pandas.core.common as com
 from pandas.core.indexes.frozen import FrozenList
-import pandas.core.dtypes.concat as _concat
 import pandas.core.missing as missing
-import pandas.core.algorithms as algos
+from pandas.core.ops import get_op_result_name, make_invalid_op
 import pandas.core.sorting as sorting
-from pandas.io.formats.printing import (
-    pprint_thing, default_pprint, format_object_summary, format_object_attrs)
-from pandas.core.ops import make_invalid_op, get_op_result_name
 from pandas.core.strings import StringMethods
 
+from pandas.io.formats.printing import (
+    default_pprint, format_object_attrs, format_object_summary, pprint_thing)
+
 __all__ = ['Index']
 
 _unsortable_types = frozenset(('mixed', 'mixed-integer'))
diff --git a/pandas/core/indexes/category.py b/pandas/core/indexes/category.py
index 6e2f0b00fcd6e..86269c7795d35 100644
--- a/pandas/core/indexes/category.py
+++ b/pandas/core/indexes/category.py
@@ -2,31 +2,28 @@
 import warnings
 
 import numpy as np
-from pandas._libs import index as libindex
 
-from pandas import compat
+from pandas._libs import index as libindex
+import pandas.compat as compat
 from pandas.compat.numpy import function as nv
-from pandas.core.dtypes.generic import ABCCategorical, ABCSeries
-from pandas.core.dtypes.dtypes import CategoricalDtype
+from pandas.util._decorators import Appender, cache_readonly
+
 from pandas.core.dtypes.common import (
-    is_categorical_dtype,
-    ensure_platform_int,
-    is_list_like,
-    is_interval_dtype,
+    ensure_platform_int, is_categorical_dtype, is_interval_dtype, is_list_like,
     is_scalar)
+from pandas.core.dtypes.dtypes import CategoricalDtype
+from pandas.core.dtypes.generic import ABCCategorical, ABCSeries
 from pandas.core.dtypes.missing import array_equivalent, isna
-from pandas.core.algorithms import take_1d
-
 
-from pandas.util._decorators import Appender, cache_readonly
-from pandas.core.config import get_option
-from pandas.core.indexes.base import Index, _index_shared_docs
 from pandas.core import accessor
+from pandas.core.algorithms import take_1d
+from pandas.core.arrays.categorical import Categorical, contains
 import pandas.core.common as com
-import pandas.core.missing as missing
+from pandas.core.config import get_option
 import pandas.core.indexes.base as ibase
+from pandas.core.indexes.base import Index, _index_shared_docs
+import pandas.core.missing as missing
 from pandas.core.ops import get_op_result_name
-from pandas.core.arrays.categorical import Categorical, contains
 
 _index_doc_kwargs = dict(ibase._index_doc_kwargs)
 _index_doc_kwargs.update(dict(target_klass='CategoricalIndex'))
diff --git a/pandas/core/indexes/frozen.py b/pandas/core/indexes/frozen.py
index cb145dd9eed4d..46731069d88b8 100644
--- a/pandas/core/indexes/frozen.py
+++ b/pandas/core/indexes/frozen.py
@@ -9,10 +9,15 @@
 """
 
 import warnings
+
 import numpy as np
-from pandas.core.base import PandasObject
+
 from pandas.util._decorators import deprecate_kwarg
+
 from pandas.core.dtypes.cast import coerce_indexer_dtype
+
+from pandas.core.base import PandasObject
+
 from pandas.io.formats.printing import pprint_thing
 
 
diff --git a/pandas/core/indexes/interval.py b/pandas/core/indexes/interval.py
index c64a179a299e9..1ebcf213ab0eb 100644
--- a/pandas/core/indexes/interval.py
+++ b/pandas/core/indexes/interval.py
@@ -4,49 +4,35 @@
 
 import numpy as np
 
+from pandas._libs import Timedelta, Timestamp
+from pandas._libs.interval import Interval, IntervalMixin, IntervalTree
 from pandas.compat import add_metaclass
-from pandas.core.dtypes.missing import isna
+from pandas.util._decorators import Appender, cache_readonly
+from pandas.util._doctools import _WritableDoc
+from pandas.util._exceptions import rewrite_exception
+
 from pandas.core.dtypes.cast import (
-    find_common_type, maybe_downcast_to_dtype, infer_dtype_from_scalar)
+    find_common_type, infer_dtype_from_scalar, maybe_downcast_to_dtype)
 from pandas.core.dtypes.common import (
-    ensure_platform_int,
-    is_list_like,
-    is_datetime_or_timedelta_dtype,
-    is_datetime64tz_dtype,
-    is_dtype_equal,
-    is_integer_dtype,
-    is_float_dtype,
-    is_interval_dtype,
-    is_object_dtype,
-    is_scalar,
-    is_float,
-    is_number,
-    is_integer)
-from pandas.core.indexes.base import (
-    Index, ensure_index,
-    default_pprint, _index_shared_docs)
-from pandas.core.ops import get_op_result_name
-
-from pandas._libs import Timestamp, Timedelta
-from pandas._libs.interval import (
-    Interval, IntervalMixin, IntervalTree,
-)
+    ensure_platform_int, is_datetime64tz_dtype, is_datetime_or_timedelta_dtype,
+    is_dtype_equal, is_float, is_float_dtype, is_integer, is_integer_dtype,
+    is_interval_dtype, is_list_like, is_number, is_object_dtype, is_scalar)
+from pandas.core.dtypes.missing import isna
 
-from pandas.core.indexes.datetimes import date_range, DatetimeIndex
-from pandas.core.indexes.timedeltas import timedelta_range, TimedeltaIndex
-from pandas.core.indexes.multi import MultiIndex
+from pandas.core.arrays.interval import IntervalArray, _interval_shared_docs
 import pandas.core.common as com
-from pandas.util._decorators import cache_readonly, Appender
-from pandas.util._doctools import _WritableDoc
-from pandas.util._exceptions import rewrite_exception
 from pandas.core.config import get_option
+import pandas.core.indexes.base as ibase
+from pandas.core.indexes.base import (
+    Index, _index_shared_docs, default_pprint, ensure_index)
+from pandas.core.indexes.datetimes import DatetimeIndex, date_range
+from pandas.core.indexes.multi import MultiIndex
+from pandas.core.indexes.timedeltas import TimedeltaIndex, timedelta_range
+from pandas.core.ops import get_op_result_name
+
 from pandas.tseries.frequencies import to_offset
 from pandas.tseries.offsets import DateOffset
 
-import pandas.core.indexes.base as ibase
-from pandas.core.arrays.interval import (IntervalArray,
-                                         _interval_shared_docs)
-
 _VALID_CLOSED = {'left', 'right', 'both', 'neither'}
 _index_doc_kwargs = dict(ibase._index_doc_kwargs)
 
diff --git a/pandas/core/indexes/multi.py b/pandas/core/indexes/multi.py
index 619e1ae866a1b..0e3fd201d8ddb 100644
--- a/pandas/core/indexes/multi.py
+++ b/pandas/core/indexes/multi.py
@@ -1,47 +1,37 @@
 
 # pylint: disable=E1101,E1103,W0232
 import datetime
-import warnings
 from sys import getsizeof
+import warnings
 
 import numpy as np
-from pandas._libs import algos as libalgos, index as libindex, lib, Timestamp
-from pandas._libs import tslibs
 
-from pandas.compat import range, zip, lrange, lzip, map
+from pandas._libs import (
+    Timestamp, algos as libalgos, index as libindex, lib, tslibs)
+import pandas.compat as compat
+from pandas.compat import lrange, lzip, map, range, zip
 from pandas.compat.numpy import function as nv
-from pandas import compat
+from pandas.errors import PerformanceWarning, UnsortedIndexError
+from pandas.util._decorators import Appender, cache_readonly
 
-from pandas.core.dtypes.dtypes import (
-    ExtensionDtype, PandasExtensionDtype)
 from pandas.core.dtypes.common import (
-    ensure_int64,
-    ensure_platform_int,
-    is_categorical_dtype,
-    is_object_dtype,
-    is_hashable,
-    is_integer,
-    is_iterator,
-    is_list_like,
-    pandas_dtype,
-    is_scalar)
-from pandas.core.dtypes.missing import isna, array_equivalent
-from pandas.errors import PerformanceWarning, UnsortedIndexError
+    ensure_int64, ensure_platform_int, is_categorical_dtype, is_hashable,
+    is_integer, is_iterator, is_list_like, is_object_dtype, is_scalar,
+    pandas_dtype)
+from pandas.core.dtypes.dtypes import ExtensionDtype, PandasExtensionDtype
+from pandas.core.dtypes.missing import array_equivalent, isna
 
-from pandas.util._decorators import Appender, cache_readonly
-import pandas.core.common as com
-import pandas.core.missing as missing
 import pandas.core.algorithms as algos
-from pandas.io.formats.printing import pprint_thing
-
+import pandas.core.common as com
 from pandas.core.config import get_option
-
+import pandas.core.indexes.base as ibase
 from pandas.core.indexes.base import (
-    Index, ensure_index,
-    InvalidIndexError,
-    _index_shared_docs)
+    Index, InvalidIndexError, _index_shared_docs, ensure_index)
 from pandas.core.indexes.frozen import FrozenList, _ensure_frozen
-import pandas.core.indexes.base as ibase
+import pandas.core.missing as missing
+
+from pandas.io.formats.printing import pprint_thing
+
 _index_doc_kwargs = dict(ibase._index_doc_kwargs)
 _index_doc_kwargs.update(
     dict(klass='MultiIndex',
diff --git a/pandas/core/indexes/numeric.py b/pandas/core/indexes/numeric.py
index 23b2dde2e6494..491176bc586a8 100644
--- a/pandas/core/indexes/numeric.py
+++ b/pandas/core/indexes/numeric.py
@@ -1,26 +1,22 @@
 import warnings
 
 import numpy as np
+
 from pandas._libs import index as libindex
+import pandas.compat as compat
+from pandas.util._decorators import Appender, cache_readonly
+
 from pandas.core.dtypes.common import (
-    is_dtype_equal,
-    pandas_dtype,
-    needs_i8_conversion,
-    is_integer_dtype,
-    is_float,
-    is_bool,
-    is_bool_dtype,
-    is_scalar)
+    is_bool, is_bool_dtype, is_dtype_equal, is_float, is_integer_dtype,
+    is_scalar, needs_i8_conversion, pandas_dtype)
+import pandas.core.dtypes.concat as _concat
 from pandas.core.dtypes.missing import isna
 
-from pandas import compat
 from pandas.core import algorithms
 import pandas.core.common as com
+import pandas.core.indexes.base as ibase
 from pandas.core.indexes.base import (
     Index, InvalidIndexError, _index_shared_docs)
-from pandas.util._decorators import Appender, cache_readonly
-import pandas.core.dtypes.concat as _concat
-import pandas.core.indexes.base as ibase
 from pandas.core.ops import get_op_result_name
 
 _num_index_shared_docs = dict()
diff --git a/pandas/core/indexes/period.py b/pandas/core/indexes/period.py
index f83687bacd72d..fec3a9bd24cc8 100644
--- a/pandas/core/indexes/period.py
+++ b/pandas/core/indexes/period.py
@@ -1,49 +1,40 @@
 # pylint: disable=E1101,E1103,W0232
 from datetime import datetime, timedelta
-import numpy as np
 import operator
 import warnings
 
-from pandas.core import common as com
-from pandas.core.dtypes.common import (
-    is_integer,
-    is_float,
-    is_float_dtype,
-    is_integer_dtype,
-    is_datetime64_any_dtype,
-    is_bool_dtype,
-    pandas_dtype
-)
-from pandas.core.ops import get_op_result_name
-from pandas.core.accessor import PandasDelegate, delegate_names
-from pandas.core.indexes.datetimes import DatetimeIndex, Int64Index, Index
-from pandas.core.indexes.datetimelike import (
-    DatelikeOps, DatetimeIndexOpsMixin, wrap_arithmetic_op
-)
-from pandas.core.tools.datetimes import parse_time_string, DateParseError
+import numpy as np
 
 from pandas._libs import index as libindex
-from pandas._libs.tslibs.period import (Period, IncompatibleFrequency,
-                                        DIFFERENT_FREQ_INDEX)
+from pandas._libs.tslibs import NaT, iNaT, resolution
+from pandas._libs.tslibs.period import (
+    DIFFERENT_FREQ_INDEX, IncompatibleFrequency, Period)
+from pandas.util._decorators import (
+    Appender, Substitution, cache_readonly, deprecate_kwarg)
 
-from pandas._libs.tslibs import resolution, NaT, iNaT
+from pandas.core.dtypes.common import (
+    is_bool_dtype, is_datetime64_any_dtype, is_float, is_float_dtype,
+    is_integer, is_integer_dtype, pandas_dtype)
 
+from pandas import compat
+from pandas.core import common as com
+from pandas.core.accessor import PandasDelegate, delegate_names
 from pandas.core.algorithms import unique1d
 import pandas.core.arrays.datetimelike as dtl
 from pandas.core.arrays.period import PeriodArray, period_array
 from pandas.core.base import _shared_docs
+import pandas.core.indexes.base as ibase
 from pandas.core.indexes.base import _index_shared_docs, ensure_index
+from pandas.core.indexes.datetimelike import (
+    DatelikeOps, DatetimeIndexOpsMixin, wrap_arithmetic_op)
+from pandas.core.indexes.datetimes import DatetimeIndex, Index, Int64Index
 from pandas.core.missing import isna
+from pandas.core.ops import get_op_result_name
+from pandas.core.tools.datetimes import DateParseError, parse_time_string
 
-from pandas import compat
-from pandas.util._decorators import (
-    Appender, Substitution, cache_readonly, deprecate_kwarg
-)
-
-from pandas.tseries.offsets import Tick, DateOffset
 from pandas.tseries import frequencies
+from pandas.tseries.offsets import DateOffset, Tick
 
-import pandas.core.indexes.base as ibase
 _index_doc_kwargs = dict(ibase._index_doc_kwargs)
 _index_doc_kwargs.update(
     dict(target_klass='PeriodIndex or list of Periods'))
diff --git a/pandas/core/indexing.py b/pandas/core/indexing.py
index 8ed181381f668..cfa451db866be 100755
--- a/pandas/core/indexing.py
+++ b/pandas/core/indexing.py
@@ -3,25 +3,18 @@
 import warnings
 
 import numpy as np
-from pandas._libs.indexing import _NDFrameIndexerBase
-from pandas.util._decorators import Appender
-
-from pandas.errors import AbstractMethodError
 
+from pandas._libs.indexing import _NDFrameIndexerBase
 import pandas.compat as compat
 from pandas.compat import range, zip
+from pandas.errors import AbstractMethodError
+from pandas.util._decorators import Appender
 
 from pandas.core.dtypes.common import (
-    is_integer_dtype,
-    is_integer, is_float,
-    is_list_like,
-    is_sequence,
-    is_iterator,
-    is_scalar,
-    is_sparse,
-    ensure_platform_int)
+    ensure_platform_int, is_float, is_integer, is_integer_dtype, is_iterator,
+    is_list_like, is_scalar, is_sequence, is_sparse)
 from pandas.core.dtypes.generic import ABCDataFrame, ABCPanel, ABCSeries
-from pandas.core.dtypes.missing import isna, _infer_fill_value
+from pandas.core.dtypes.missing import _infer_fill_value, isna
 
 import pandas.core.common as com
 from pandas.core.index import Index, MultiIndex
diff --git a/pandas/core/missing.py b/pandas/core/missing.py
index 222873cd7f81a..1012639fe0f9d 100644
--- a/pandas/core/missing.py
+++ b/pandas/core/missing.py
@@ -1,26 +1,19 @@
 """
 Routines for filling missing data
 """
+from distutils.version import LooseVersion
 import operator
 
 import numpy as np
-from distutils.version import LooseVersion
 
 from pandas._libs import algos, lib
-
 from pandas.compat import range, string_types
-from pandas.core.dtypes.common import (
-    is_numeric_v_string_like,
-    is_float_dtype,
-    is_datetime64_dtype,
-    is_datetime64tz_dtype,
-    is_integer_dtype,
-    is_scalar,
-    is_integer,
-    needs_i8_conversion,
-    ensure_float64)
 
 from pandas.core.dtypes.cast import infer_dtype_from_array
+from pandas.core.dtypes.common import (
+    ensure_float64, is_datetime64_dtype, is_datetime64tz_dtype, is_float_dtype,
+    is_integer, is_integer_dtype, is_numeric_v_string_like, is_scalar,
+    needs_i8_conversion)
 from pandas.core.dtypes.missing import isna
 
 
diff --git a/pandas/core/nanops.py b/pandas/core/nanops.py
index afba433f0e391..4369ac60a075e 100644
--- a/pandas/core/nanops.py
+++ b/pandas/core/nanops.py
@@ -1,27 +1,24 @@
+from distutils.version import LooseVersion
 import functools
 import itertools
 import operator
 import warnings
-from distutils.version import LooseVersion
 
 import numpy as np
 
-import pandas.core.common as com
-from pandas import compat
-from pandas._libs import tslibs, lib
-from pandas.core.config import get_option
+from pandas._libs import lib, tslibs
+import pandas.compat as compat
+
 from pandas.core.dtypes.cast import _int64_max, maybe_upcast_putmask
 from pandas.core.dtypes.common import (
-    _get_dtype,
-    is_float, is_scalar,
-    is_integer, is_complex, is_float_dtype,
-    is_complex_dtype, is_integer_dtype,
-    is_bool_dtype, is_object_dtype,
-    is_numeric_dtype,
-    is_datetime64_dtype, is_timedelta64_dtype,
-    is_datetime_or_timedelta_dtype,
-    is_int_or_datetime_dtype, is_any_int_dtype)
-from pandas.core.dtypes.missing import isna, notna, na_value_for_dtype
+    _get_dtype, is_any_int_dtype, is_bool_dtype, is_complex, is_complex_dtype,
+    is_datetime64_dtype, is_datetime_or_timedelta_dtype, is_float,
+    is_float_dtype, is_int_or_datetime_dtype, is_integer, is_integer_dtype,
+    is_numeric_dtype, is_object_dtype, is_scalar, is_timedelta64_dtype)
+from pandas.core.dtypes.missing import isna, na_value_for_dtype, notna
+
+import pandas.core.common as com
+from pandas.core.config import get_option
 
 _BOTTLENECK_INSTALLED = False
 _MIN_BOTTLENECK_VERSION = '1.0.0'
diff --git a/pandas/core/ops.py b/pandas/core/ops.py
index 869a1d6e2fb14..2a21593fab8f5 100644
--- a/pandas/core/ops.py
+++ b/pandas/core/ops.py
@@ -5,50 +5,41 @@
 """
 # necessary to enforce truediv in Python 2.X
 from __future__ import division
+
 import datetime
 import operator
 import textwrap
 import warnings
 
 import numpy as np
-import pandas as pd
-
-from pandas._libs import lib, algos as libalgos, ops as libops
-
-from pandas import compat
-from pandas.util._decorators import Appender
 
+from pandas._libs import algos as libalgos, lib, ops as libops
+import pandas.compat as compat
 from pandas.compat import bind_method
-import pandas.core.missing as missing
-import pandas.core.common as com
-
 from pandas.errors import NullFrequencyError
-from pandas.core.dtypes.missing import notna, isna
-from pandas.core.dtypes.common import (
-    needs_i8_conversion,
-    is_datetimelike_v_numeric,
-    is_period_dtype,
-    is_integer_dtype, is_categorical_dtype,
-    is_object_dtype, is_timedelta64_dtype,
-    is_datetime64_dtype, is_datetime64tz_dtype,
-    is_bool_dtype,
-    is_list_like,
-    is_scalar,
-    is_extension_array_dtype,
-    ensure_object)
+from pandas.util._decorators import Appender
+
 from pandas.core.dtypes.cast import (
-    maybe_upcast_putmask, find_common_type,
-    construct_1d_object_array_from_listlike)
+    construct_1d_object_array_from_listlike, find_common_type,
+    maybe_upcast_putmask)
+from pandas.core.dtypes.common import (
+    ensure_object, is_bool_dtype, is_categorical_dtype, is_datetime64_dtype,
+    is_datetime64tz_dtype, is_datetimelike_v_numeric, is_extension_array_dtype,
+    is_integer_dtype, is_list_like, is_object_dtype, is_period_dtype,
+    is_scalar, is_timedelta64_dtype, needs_i8_conversion)
 from pandas.core.dtypes.generic import (
-    ABCSeries,
-    ABCDataFrame, ABCPanel,
-    ABCIndex, ABCIndexClass,
-    ABCSparseSeries, ABCSparseArray)
+    ABCDataFrame, ABCIndex, ABCIndexClass, ABCPanel, ABCSeries, ABCSparseArray,
+    ABCSparseSeries)
+from pandas.core.dtypes.missing import isna, notna
 
+import pandas as pd
+import pandas.core.common as com
+import pandas.core.missing as missing
 
 # -----------------------------------------------------------------------------
 # Ops Wrapping Utilities
 
+
 def get_op_result_name(left, right):
     """
     Find the appropriate name to pin to an operation result.  This result
diff --git a/pandas/core/panel.py b/pandas/core/panel.py
index 5ae7848b5adc6..bf076b306a9ad 100644
--- a/pandas/core/panel.py
+++ b/pandas/core/panel.py
@@ -4,36 +4,37 @@
 # pylint: disable=E1103,W0231,W0212,W0621
 from __future__ import division
 
-import numpy as np
 import warnings
+
+import numpy as np
+
+import pandas.compat as compat
+from pandas.compat import OrderedDict, map, range, u, zip
+from pandas.compat.numpy import function as nv
+from pandas.util._decorators import Appender, Substitution, deprecate_kwarg
+from pandas.util._validators import validate_axis_style_args
+
 from pandas.core.dtypes.cast import (
-    infer_dtype_from_scalar,
-    cast_scalar_to_array,
-    maybe_cast_item)
+    cast_scalar_to_array, infer_dtype_from_scalar, maybe_cast_item)
 from pandas.core.dtypes.common import (
-    is_integer, is_list_like,
-    is_string_like, is_scalar)
+    is_integer, is_list_like, is_scalar, is_string_like)
 from pandas.core.dtypes.missing import notna
 
-import pandas.core.ops as ops
 import pandas.core.common as com
-import pandas.core.indexes.base as ibase
-from pandas import compat
-from pandas.compat import (map, zip, range, u, OrderedDict)
-from pandas.compat.numpy import function as nv
 from pandas.core.frame import DataFrame
 from pandas.core.generic import NDFrame, _shared_docs
-from pandas.core.index import (Index, MultiIndex, ensure_index,
-                               _get_objs_combined_axis)
-from pandas.io.formats.printing import pprint_thing
+from pandas.core.index import (
+    Index, MultiIndex, _get_objs_combined_axis, ensure_index)
+import pandas.core.indexes.base as ibase
 from pandas.core.indexing import maybe_droplevels
-from pandas.core.internals import (BlockManager,
-                                   create_block_manager_from_arrays,
-                                   create_block_manager_from_blocks)
-from pandas.core.series import Series
+from pandas.core.internals import (
+    BlockManager, create_block_manager_from_arrays,
+    create_block_manager_from_blocks)
+import pandas.core.ops as ops
 from pandas.core.reshape.util import cartesian_product
-from pandas.util._decorators import Appender, Substitution, deprecate_kwarg
-from pandas.util._validators import validate_axis_style_args
+from pandas.core.series import Series
+
+from pandas.io.formats.printing import pprint_thing
 
 _shared_doc_kwargs = dict(
     axes='items, major_axis, minor_axis',
diff --git a/pandas/core/resample.py b/pandas/core/resample.py
index 26b1e33e9893b..4f0669a568ae7 100644
--- a/pandas/core/resample.py
+++ b/pandas/core/resample.py
@@ -1,37 +1,37 @@
-from datetime import timedelta
-import numpy as np
-import warnings
 import copy
+from datetime import timedelta
 from textwrap import dedent
+import warnings
+
+import numpy as np
+
+from pandas._libs import lib
+from pandas._libs.tslibs import NaT, Timestamp
+from pandas._libs.tslibs.period import IncompatibleFrequency
+import pandas.compat as compat
+from pandas.compat.numpy import function as nv
+from pandas.errors import AbstractMethodError
+from pandas.util._decorators import Appender, Substitution
+
+from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
 
 import pandas as pd
+import pandas.core.algorithms as algos
+from pandas.core.generic import _shared_docs
 from pandas.core.groupby.base import GroupByMixin
-from pandas.core.groupby.ops import BinGrouper
+from pandas.core.groupby.generic import PanelGroupBy, SeriesGroupBy
 from pandas.core.groupby.groupby import (
-    _GroupBy, GroupBy, groupby, _pipe_template
-)
+    GroupBy, _GroupBy, _pipe_template, groupby)
 from pandas.core.groupby.grouper import Grouper
-from pandas.core.groupby.generic import SeriesGroupBy, PanelGroupBy
-
-from pandas.tseries.frequencies import to_offset, is_subperiod, is_superperiod
+from pandas.core.groupby.ops import BinGrouper
 from pandas.core.indexes.datetimes import DatetimeIndex, date_range
-from pandas.core.indexes.timedeltas import TimedeltaIndex
-from pandas.tseries.offsets import (DateOffset, Tick, Day,
-                                    delta_to_nanoseconds, Nano)
 from pandas.core.indexes.period import PeriodIndex
-from pandas.errors import AbstractMethodError
-import pandas.core.algorithms as algos
-from pandas.core.dtypes.generic import ABCDataFrame, ABCSeries
-
-import pandas.compat as compat
-from pandas.compat.numpy import function as nv
+from pandas.core.indexes.timedeltas import TimedeltaIndex
 
-from pandas._libs import lib
-from pandas._libs.tslibs import Timestamp, NaT
-from pandas._libs.tslibs.period import IncompatibleFrequency
+from pandas.tseries.frequencies import is_subperiod, is_superperiod, to_offset
+from pandas.tseries.offsets import (
+    DateOffset, Day, Nano, Tick, delta_to_nanoseconds)
 
-from pandas.util._decorators import Appender, Substitution
-from pandas.core.generic import _shared_docs
 _shared_docs_kwargs = dict()
 
 
diff --git a/pandas/core/sorting.py b/pandas/core/sorting.py
index ee1c62f3decf9..b34dfddcc66e1 100644
--- a/pandas/core/sorting.py
+++ b/pandas/core/sorting.py
@@ -1,18 +1,17 @@
 """ miscellaneous sorting / groupby utilities """
 
 import numpy as np
-from pandas.compat import long, string_types, PY3
-from pandas.core.dtypes.common import (
-    ensure_platform_int,
-    ensure_int64,
-    is_list_like,
-    is_categorical_dtype)
+
+from pandas._libs import algos, hashtable, lib
+from pandas._libs.hashtable import unique_label_indices
+from pandas.compat import PY3, long, string_types
+
 from pandas.core.dtypes.cast import infer_dtype_from_array
+from pandas.core.dtypes.common import (
+    ensure_int64, ensure_platform_int, is_categorical_dtype, is_list_like)
 from pandas.core.dtypes.missing import isna
-import pandas.core.algorithms as algorithms
-from pandas._libs import lib, algos, hashtable
-from pandas._libs.hashtable import unique_label_indices
 
+import pandas.core.algorithms as algorithms
 
 _INT64_MAX = np.iinfo(np.int64).max
 
diff --git a/pandas/core/strings.py b/pandas/core/strings.py
index 6c21318c93597..0b791f6f91aa3 100644
--- a/pandas/core/strings.py
+++ b/pandas/core/strings.py
@@ -1,31 +1,26 @@
 # -*- coding: utf-8 -*-
+import codecs
+import re
+import textwrap
+import warnings
+
 import numpy as np
 
+import pandas._libs.lib as lib
+import pandas._libs.ops as libops
+import pandas.compat as compat
 from pandas.compat import zip
-from pandas.core.dtypes.generic import ABCSeries, ABCIndex
-from pandas.core.dtypes.missing import isna
+from pandas.util._decorators import Appender, deprecate_kwarg
+
 from pandas.core.dtypes.common import (
-    ensure_object,
-    is_bool_dtype,
-    is_categorical_dtype,
-    is_object_dtype,
-    is_string_like,
-    is_list_like,
-    is_scalar,
-    is_integer,
-    is_re)
+    ensure_object, is_bool_dtype, is_categorical_dtype, is_integer,
+    is_list_like, is_object_dtype, is_re, is_scalar, is_string_like)
+from pandas.core.dtypes.generic import ABCIndex, ABCSeries
+from pandas.core.dtypes.missing import isna
 
-import pandas.core.common as com
 from pandas.core.algorithms import take_1d
-import pandas.compat as compat
 from pandas.core.base import NoNewAttributesMixin
-from pandas.util._decorators import Appender, deprecate_kwarg
-import re
-import pandas._libs.lib as lib
-import pandas._libs.ops as libops
-import warnings
-import textwrap
-import codecs
+import pandas.core.common as com
 
 _cpython_optimized_encoders = (
     "utf-8", "utf8", "latin-1", "latin1", "iso-8859-1", "mbcs", "ascii"
diff --git a/setup.cfg b/setup.cfg
index e8db1308741aa..4027e040cf421 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -111,33 +111,8 @@ force_grid_wrap=0
 combine_as_imports=True
 force_sort_within_sections=True
 skip=
-    pandas/core/ops.py,
-    pandas/core/categorical.py,
     pandas/core/api.py,
-    pandas/core/indexing.py,
-    pandas/core/apply.py,
-    pandas/core/generic.py,
-    pandas/core/sorting.py,
     pandas/core/frame.py,
-    pandas/core/nanops.py,
-    pandas/core/algorithms.py,
-    pandas/core/strings.py,
-    pandas/core/panel.py,
-    pandas/core/config.py,
-    pandas/core/resample.py,
-    pandas/core/base.py,
-    pandas/core/common.py,
-    pandas/core/missing.py,
-    pandas/core/config_init.py,
-    pandas/core/indexes/category.py,
-    pandas/core/indexes/api.py,
-    pandas/core/indexes/numeric.py,
-    pandas/core/indexes/interval.py,
-    pandas/core/indexes/multi.py,
-    pandas/core/indexes/base.py,
-    pandas/core/indexes/accessors.py,
-    pandas/core/indexes/period.py,
-    pandas/core/indexes/frozen.py,
     pandas/tests/test_errors.py,
     pandas/tests/test_base.py,
     pandas/tests/test_register_accessor.py,