From 1c6b957597fad5915b47d57834940dd98ecc4469 Mon Sep 17 00:00:00 2001
From: MomIsBestFriend <>
Date: Sat, 21 Dec 2019 16:54:59 +0200
Subject: [PATCH 1/2] TYP

---
 pandas/core/indexers.py             |   5 +-
 pandas/core/indexes/accessors.py    |  13 ++--
 pandas/core/indexes/api.py          |   2 -
 pandas/core/indexes/base.py         |  10 ++-
 pandas/core/indexes/category.py     |   4 +-
 pandas/core/indexes/datetimelike.py |  11 +--
 pandas/core/indexes/datetimes.py    |  55 ++++++++++-----
 pandas/core/indexes/frozen.py       |   8 ++-
 pandas/core/indexes/interval.py     | 102 +++++++++++++++++-----------
 pandas/core/indexes/multi.py        |  41 +++++------
 pandas/core/indexes/numeric.py      |  30 ++++----
 pandas/io/formats/console.py        |  17 +++--
 12 files changed, 175 insertions(+), 123 deletions(-)

diff --git a/pandas/core/indexers.py b/pandas/core/indexers.py
index 209f889e809c3..ac1b0ab766a03 100644
--- a/pandas/core/indexers.py
+++ b/pandas/core/indexers.py
@@ -144,8 +144,9 @@ def validate_indices(indices: np.ndarray, n: int) -> None:
     if len(indices):
         min_idx = indices.min()
         if min_idx < -1:
-            msg = f"'indices' contains values less than allowed ({min_idx} < -1)"
-            raise ValueError(msg)
+            raise ValueError(
+                f"'indices' contains values less than allowed ({min_idx} < -1)"
+            )
 
         max_idx = indices.max()
         if max_idx >= n:
diff --git a/pandas/core/indexes/accessors.py b/pandas/core/indexes/accessors.py
index ae27aad3dda08..db774a03c02f8 100644
--- a/pandas/core/indexes/accessors.py
+++ b/pandas/core/indexes/accessors.py
@@ -26,8 +26,7 @@ class Properties(PandasDelegate, PandasObject, NoNewAttributesMixin):
     def __init__(self, data, orig):
         if not isinstance(data, ABCSeries):
             raise TypeError(
-                f"cannot convert an object of type {type(data)} to a "
-                "datetimelike index"
+                f"cannot convert an object of type {type(data)} to a datetimelike index"
             )
 
         self._parent = data
@@ -91,9 +90,8 @@ def _delegate_property_get(self, name):
 
     def _delegate_property_set(self, name, value, *args, **kwargs):
         raise ValueError(
-            "modifications to a property of a datetimelike "
-            "object are not supported. Change values on the "
-            "original."
+            "modifications to a property of a datetimelike object are not supported. "
+            "Change values on the original."
         )
 
     def _delegate_method(self, name, *args, **kwargs):
@@ -222,7 +220,7 @@ def to_pytimedelta(self):
 
         Returns
         -------
-        a : numpy.ndarray
+        numpy.ndarray
             Array of 1D containing data with `datetime.timedelta` type.
 
         See Also
@@ -314,8 +312,7 @@ def __new__(cls, data):
 
         if not isinstance(data, ABCSeries):
             raise TypeError(
-                f"cannot convert an object of type {type(data)} to a "
-                "datetimelike index"
+                f"cannot convert an object of type {type(data)} to a datetimelike index"
             )
 
         orig = data if is_categorical_dtype(data) else None
diff --git a/pandas/core/indexes/api.py b/pandas/core/indexes/api.py
index e99ae96f35315..1904456848396 100644
--- a/pandas/core/indexes/api.py
+++ b/pandas/core/indexes/api.py
@@ -124,7 +124,6 @@ def _get_combined_index(
     -------
     Index
     """
-
     # TODO: handle index names!
     indexes = _get_distinct_objs(indexes)
     if len(indexes) == 0:
@@ -273,7 +272,6 @@ def get_consensus_names(indexes):
     list
         A list representing the consensus 'names' found.
     """
-
     # find the non-none names, need to tupleify to make
     # the set hashable, then reverse on return
     consensus_names = {tuple(i.names) for i in indexes if com.any_not_none(*i.names)}
diff --git a/pandas/core/indexes/base.py b/pandas/core/indexes/base.py
index 5abd049b9564c..ce7a238daeca9 100644
--- a/pandas/core/indexes/base.py
+++ b/pandas/core/indexes/base.py
@@ -804,11 +804,10 @@ def _assert_take_fillable(
         # only fill if we are passing a non-None fill_value
         if allow_fill and fill_value is not None:
             if (indices < -1).any():
-                msg = (
+                raise ValueError(
                     "When allow_fill=True and fill_value is not None, "
                     "all indices must be >= -1"
                 )
-                raise ValueError(msg)
             taken = algos.take(
                 values, indices, allow_fill=allow_fill, fill_value=na_value
             )
@@ -1324,8 +1323,7 @@ def set_names(self, names, level=None, inplace=False):
             raise ValueError("Level must be None for non-MultiIndex")
 
         if level is not None and not is_list_like(level) and is_list_like(names):
-            msg = "Names must be a string when a single level is provided."
-            raise TypeError(msg)
+            raise TypeError("Names must be a string when a single level is provided.")
 
         if not is_list_like(names) and level is None and self.nlevels > 1:
             raise TypeError("Must pass list-like as `names`.")
@@ -1421,8 +1419,8 @@ def _validate_index_level(self, level):
         if isinstance(level, int):
             if level < 0 and level != -1:
                 raise IndexError(
-                    f"Too many levels: Index has only 1 level,"
-                    f" {level} is not a valid level number"
+                    "Too many levels: Index has only 1 level, "
+                    f"{level} is not a valid level number"
                 )
             elif level > 0:
                 raise IndexError(
diff --git a/pandas/core/indexes/category.py b/pandas/core/indexes/category.py
index 44478d00da9cf..d35117b8db86e 100644
--- a/pandas/core/indexes/category.py
+++ b/pandas/core/indexes/category.py
@@ -715,9 +715,7 @@ def _convert_list_indexer(self, keyarr, kind=None):
         indexer = self.categories.get_indexer(np.asarray(keyarr))
         if (indexer == -1).any():
             raise KeyError(
-                "a list-indexer must only "
-                "include values that are "
-                "in the categories"
+                "a list-indexer must only include values that are in the categories"
             )
 
         return self.get_indexer(keyarr)
diff --git a/pandas/core/indexes/datetimelike.py b/pandas/core/indexes/datetimelike.py
index 50dbddec5c8b2..3bf6dce00a031 100644
--- a/pandas/core/indexes/datetimelike.py
+++ b/pandas/core/indexes/datetimelike.py
@@ -2,7 +2,7 @@
 Base and utility classes for tseries type pandas objects.
 """
 import operator
-from typing import Set
+from typing import List, Set
 
 import numpy as np
 
@@ -73,7 +73,7 @@ def method(self, other):
 
 class DatetimeIndexOpsMixin(ExtensionOpsMixin):
     """
-    common ops mixin to support a unified interface datetimelike Index
+    Common ops mixin to support a unified interface datetimelike Index.
     """
 
     _data: ExtensionArray
@@ -336,7 +336,7 @@ def _convert_tolerance(self, tolerance, target):
             raise ValueError("list-like tolerance size must match target index size")
         return tolerance
 
-    def tolist(self):
+    def tolist(self) -> List:
         """
         Return a list of the underlying data.
         """
@@ -661,11 +661,12 @@ def _summary(self, name=None):
         Parameters
         ----------
         name : str
-            name to use in the summary representation
+            Name to use in the summary representation.
 
         Returns
         -------
-        String with a summarized representation of the index
+        str
+            Summarized representation of the index.
         """
         formatter = self._formatter_func
         if len(self) > 0:
diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index 523c434cb7377..1fd962dd24656 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -45,9 +45,10 @@
 
 
 def _new_DatetimeIndex(cls, d):
-    """ This is called upon unpickling, rather than the default which doesn't
-    have arguments and breaks __new__ """
-
+    """
+    This is called upon unpickling, rather than the default which doesn't
+    have arguments and breaks __new__
+    """
     if "data" in d and not isinstance(d["data"], DatetimeIndex):
         # Avoid need to verify integrity by calling simple_new directly
         data = d.pop("data")
@@ -100,9 +101,9 @@ class DatetimeIndex(DatetimeIndexOpsMixin, Int64Index, DatetimeDelegateMixin):
 
     Parameters
     ----------
-    data  : array-like (1-dimensional), optional
+    data : array-like (1-dimensional), optional
         Optional datetime-like data to construct index with.
-    copy  : bool
+    copy : bool
         Make a copy of input ndarray.
     freq : str or pandas offset object, optional
         One of pandas date offset strings or corresponding objects. The string
@@ -273,7 +274,7 @@ def __new__(
     @classmethod
     def _simple_new(cls, values, name=None, freq=None, tz=None, dtype=None):
         """
-        we require the we have a dtype compat for the values
+        We require the we have a dtype compat for the values
         if we are passed a non-dtype compat, then coerce using the constructor
         """
         if isinstance(values, DatetimeArray):
@@ -345,7 +346,13 @@ def tz(self, value):
 
     @cache_readonly
     def _is_dates_only(self) -> bool:
-        """Return a boolean if we are only dates (and don't have a timezone)"""
+        """
+        Return a boolean if we are only dates (and don't have a timezone)
+
+        Returns
+        -------
+        bool
+        """
         from pandas.io.formats.format import _is_dates_only
 
         return _is_dates_only(self.values) and self.tz is None
@@ -360,7 +367,9 @@ def __reduce__(self):
         return _new_DatetimeIndex, (type(self), d), None
 
     def __setstate__(self, state):
-        """Necessary for making this object picklable"""
+        """
+        Necessary for making this object picklable.
+        """
         if isinstance(state, dict):
             super().__setstate__(state)
 
@@ -393,7 +402,9 @@ def __setstate__(self, state):
     _unpickle_compat = __setstate__
 
     def _convert_for_op(self, value):
-        """ Convert value to be insertable to ndarray """
+        """
+        Convert value to be insertable to ndarray.
+        """
         if self._has_same_tz(value):
             return _to_M8(value)
         raise ValueError("Passed item and index have different timezone")
@@ -461,7 +472,7 @@ def _union(self, other, sort):
 
     def union_many(self, others):
         """
-        A bit of a hack to accelerate unioning a collection of indexes
+        A bit of a hack to accelerate unioning a collection of indexes.
         """
         this = self
 
@@ -489,7 +500,7 @@ def union_many(self, others):
                     this._data._dtype = dtype
         return this
 
-    def _can_fast_union(self, other):
+    def _can_fast_union(self, other) -> bool:
         if not isinstance(other, DatetimeIndex):
             return False
 
@@ -581,7 +592,7 @@ def intersection(self, other, sort=False):
 
         Returns
         -------
-        y : Index or DatetimeIndex or TimedeltaIndex
+        Index or DatetimeIndex or TimedeltaIndex
         """
         return super().intersection(other, sort=sort)
 
@@ -699,7 +710,9 @@ def snap(self, freq="S"):
         # we know it conforms; skip check
         return DatetimeIndex._simple_new(snapped, name=self.name, tz=self.tz, freq=freq)
 
-    def join(self, other, how="left", level=None, return_indexers=False, sort=False):
+    def join(
+        self, other, how: str = "left", level=None, return_indexers=False, sort=False
+    ):
         """
         See Index.join
         """
@@ -840,9 +853,8 @@ def _parsed_string_to_bounds(self, reso, parsed):
         if parsed.tzinfo is not None:
             if self.tz is None:
                 raise ValueError(
-                    "The index must be timezone aware "
-                    "when indexing with a date string with a "
-                    "UTC offset"
+                    "The index must be timezone aware when indexing "
+                    "with a date string with a UTC offset"
                 )
             start = start.tz_localize(parsed.tzinfo).tz_convert(self.tz)
             end = end.tz_localize(parsed.tzinfo).tz_convert(self.tz)
@@ -851,7 +863,16 @@ def _parsed_string_to_bounds(self, reso, parsed):
             end = end.tz_localize(self.tz)
         return start, end
 
-    def _partial_date_slice(self, reso, parsed, use_lhs=True, use_rhs=True):
+    def _partial_date_slice(
+        self, reso: str, parsed, use_lhs: bool = True, use_rhs: bool = True
+    ):
+        """
+        Parameters
+        ----------
+        reso : str
+        use_lhs : bool, default True
+        use_rhs : bool, default True
+        """
         is_monotonic = self.is_monotonic
         if (
             is_monotonic
diff --git a/pandas/core/indexes/frozen.py b/pandas/core/indexes/frozen.py
index fd8ab74ed4920..909643d50e9d7 100644
--- a/pandas/core/indexes/frozen.py
+++ b/pandas/core/indexes/frozen.py
@@ -35,7 +35,7 @@ def union(self, other) -> "FrozenList":
 
         Returns
         -------
-        diff : FrozenList
+        FrozenList
             The collection difference between self and other.
         """
         if isinstance(other, tuple):
@@ -53,7 +53,7 @@ def difference(self, other) -> "FrozenList":
 
         Returns
         -------
-        diff : FrozenList
+        FrozenList
             The collection difference between self and other.
         """
         other = set(other)
@@ -92,7 +92,9 @@ def __hash__(self):
         return hash(tuple(self))
 
     def _disabled(self, *args, **kwargs):
-        """This method will not function because object is immutable."""
+        """
+        This method will not function because object is immutable.
+        """
         raise TypeError(f"'{type(self).__name__}' does not support mutable operations.")
 
     def __str__(self) -> str:
diff --git a/pandas/core/indexes/interval.py b/pandas/core/indexes/interval.py
index f046f0d89c428..dee4c959f8c90 100644
--- a/pandas/core/indexes/interval.py
+++ b/pandas/core/indexes/interval.py
@@ -143,21 +143,19 @@ def func(intvidx_self, other, sort=False):
                     result = result.astype(intvidx_self.dtype)
                 return result
             elif intvidx_self.closed != other.closed:
-                msg = (
+                raise ValueError(
                     "can only do set operations between two IntervalIndex "
                     "objects that are closed on the same side"
                 )
-                raise ValueError(msg)
 
             # GH 19016: ensure set op will not return a prohibited dtype
             subtypes = [intvidx_self.dtype.subtype, other.dtype.subtype]
             common_subtype = find_common_type(subtypes)
             if is_object_dtype(common_subtype):
-                msg = (
+                raise TypeError(
                     f"can only do {self.op_name} between two IntervalIndex "
                     "objects that have compatible dtypes"
                 )
-                raise TypeError(msg)
 
             return setop(intvidx_self, other, sort)
 
@@ -210,7 +208,13 @@ class IntervalIndex(IntervalMixin, Index):
     # Constructors
 
     def __new__(
-        cls, data, closed=None, dtype=None, copy=False, name=None, verify_integrity=True
+        cls,
+        data,
+        closed=None,
+        dtype=None,
+        copy: bool = False,
+        name=None,
+        verify_integrity: bool = True,
     ):
 
         if name is None and hasattr(data, "name"):
@@ -263,7 +267,9 @@ def _simple_new(cls, array, name, closed=None):
             ),
         )
     )
-    def from_breaks(cls, breaks, closed="right", name=None, copy=False, dtype=None):
+    def from_breaks(
+        cls, breaks, closed: str = "right", name=None, copy: bool = False, dtype=None
+    ):
         with rewrite_exception("IntervalArray", cls.__name__):
             array = IntervalArray.from_breaks(
                 breaks, closed=closed, copy=copy, dtype=dtype
@@ -288,7 +294,13 @@ def from_breaks(cls, breaks, closed="right", name=None, copy=False, dtype=None):
         )
     )
     def from_arrays(
-        cls, left, right, closed="right", name=None, copy=False, dtype=None
+        cls,
+        left,
+        right,
+        closed: str = "right",
+        name=None,
+        copy: bool = False,
+        dtype=None,
     ):
         with rewrite_exception("IntervalArray", cls.__name__):
             array = IntervalArray.from_arrays(
@@ -313,7 +325,9 @@ def from_arrays(
             ),
         )
     )
-    def from_tuples(cls, data, closed="right", name=None, copy=False, dtype=None):
+    def from_tuples(
+        cls, data, closed: str = "right", name=None, copy: bool = False, dtype=None
+    ):
         with rewrite_exception("IntervalArray", cls.__name__):
             arr = IntervalArray.from_tuples(data, closed=closed, copy=copy, dtype=dtype)
         return cls._simple_new(arr, name=name)
@@ -329,7 +343,9 @@ def _shallow_copy(self, left=None, right=None, **kwargs):
 
     @cache_readonly
     def _isnan(self):
-        """Return a mask indicating if each value is NA"""
+        """
+        Return a mask indicating if each value is NA.
+        """
         if self._mask is None:
             self._mask = isna(self.left)
         return self._mask
@@ -351,7 +367,7 @@ def __contains__(self, key) -> bool:
 
         Returns
         -------
-        boolean
+        bool
         """
         if not isinstance(key, Interval):
             return False
@@ -470,7 +486,9 @@ def _ndarray_values(self) -> np.ndarray:
         return np.array(self._data)
 
     def __array__(self, result=None):
-        """ the array interface, return my values """
+        """
+        The array interface, return my values.
+        """
         return self._ndarray_values
 
     def __array_wrap__(self, result, context=None):
@@ -503,7 +521,9 @@ def astype(self, dtype, copy=True):
 
     @cache_readonly
     def dtype(self):
-        """Return the dtype object of the underlying data"""
+        """
+        Return the dtype object of the underlying data.
+        """
         return self._data.dtype
 
     @property
@@ -551,7 +571,7 @@ def is_monotonic_decreasing(self) -> bool:
     @cache_readonly
     def is_unique(self):
         """
-        Return True if the IntervalIndex contains unique elements, else False
+        Return True if the IntervalIndex contains unique elements, else False.
         """
         left = self.left
         right = self.right
@@ -708,7 +728,7 @@ def _needs_i8_conversion(self, key):
 
         Returns
         -------
-        boolean
+        bool
         """
         if is_interval_dtype(key) or isinstance(key, Interval):
             return self._needs_i8_conversion(key.left)
@@ -729,7 +749,7 @@ def _maybe_convert_i8(self, key):
 
         Returns
         -------
-        key: scalar or list-like
+        scalar or list-like
             The original key if no conversion occurred, int if converted scalar,
             Int64Index if converted list-like.
         """
@@ -775,22 +795,21 @@ def _check_method(self, method):
             return
 
         if method in ["bfill", "backfill", "pad", "ffill", "nearest"]:
-            msg = f"method {method} not yet implemented for IntervalIndex"
-            raise NotImplementedError(msg)
+            raise NotImplementedError(
+                f"method {method} not yet implemented for IntervalIndex"
+            )
 
         raise ValueError("Invalid fill method")
 
     def _searchsorted_monotonic(self, label, side, exclude_label=False):
         if not self.is_non_overlapping_monotonic:
             raise KeyError(
-                "can only get slices from an IntervalIndex if "
-                "bounds are non-overlapping and all monotonic "
-                "increasing or decreasing"
+                "can only get slices from an IntervalIndex if bounds are "
+                "non-overlapping and all monotonic increasing or decreasing"
             )
 
         if isinstance(label, IntervalMixin):
-            msg = "Interval objects are not currently supported"
-            raise NotImplementedError(msg)
+            raise NotImplementedError("Interval objects are not currently supported")
 
         # GH 20921: "not is_monotonic_increasing" for the second condition
         # instead of "is_monotonic_decreasing" to account for single element
@@ -850,7 +869,7 @@ def get_loc(
 
         Returns
         -------
-        loc : int if unique index, slice if monotonic index, else mask
+        int if unique index, slice if monotonic index, else mask
 
         Examples
         --------
@@ -933,11 +952,10 @@ def get_indexer(
         self._check_method(method)
 
         if self.is_overlapping:
-            msg = (
-                "cannot handle overlapping indices; use "
-                "IntervalIndex.get_indexer_non_unique"
+            raise InvalidIndexError(
+                "cannot handle overlapping indices; "
+                "use IntervalIndex.get_indexer_non_unique"
             )
-            raise InvalidIndexError(msg)
 
         target_as_index = ensure_index(target)
 
@@ -1071,7 +1089,7 @@ def delete(self, loc):
 
         Returns
         -------
-        new_index : IntervalIndex
+        IntervalIndex
         """
         new_left = self.left.delete(loc)
         new_right = self.right.delete(loc)
@@ -1090,7 +1108,7 @@ def insert(self, loc, item):
 
         Returns
         -------
-        new_index : IntervalIndex
+        IntervalIndex
         """
         if isinstance(item, Interval):
             if item.closed != self.closed:
@@ -1117,11 +1135,10 @@ def _concat_same_dtype(self, to_concat, name):
         we allow a 0-len index here as well
         """
         if not len({i.closed for i in to_concat if len(i)}) == 1:
-            msg = (
+            raise ValueError(
                 "can only append two IntervalIndex objects "
                 "that are closed on the same side"
             )
-            raise ValueError(msg)
         return super()._concat_same_dtype(to_concat, name)
 
     @Appender(_index_shared_docs["take"] % _index_doc_kwargs)
@@ -1175,10 +1192,13 @@ def _format_data(self, name=None):
                 n = min(max_seq_items // 2, 10)
                 head = [formatter(x) for x in self[:n]]
                 tail = [formatter(x) for x in self[-n:]]
-                summary = f"[{', '.join(head)} ... {', '.join(tail)}]"
+                head_joined = ", ".join(head)
+                tail_joined = ", ".join(tail)
+                summary = f"[{head_joined} ... {tail_joined}]"
             else:
                 tail = [formatter(x) for x in self]
-                summary = f"[{', '.join(tail)}]"
+                joined = ", ".join(tail)
+                summary = f"[{joined}]"
 
         return summary + "," + self._format_space()
 
@@ -1189,7 +1209,7 @@ def _format_attrs(self):
         attrs.append(("dtype", f"'{self.dtype}'"))
         return attrs
 
-    def _format_space(self):
+    def _format_space(self) -> str:
         space = " " * (len(type(self).__name__) + 1)
         return f"\n{space}"
 
@@ -1200,7 +1220,7 @@ def argsort(self, *args, **kwargs):
 
     def equals(self, other) -> bool:
         """
-        Determines if two IntervalIndex objects contain the same elements
+        Determines if two IntervalIndex objects contain the same elements.
         """
         if self.is_(other):
             return True
@@ -1288,7 +1308,7 @@ def _intersection_unique(self, other: "IntervalIndex") -> "IntervalIndex":
 
         Returns
         -------
-        taken : IntervalIndex
+        IntervalIndex
         """
         lindexer = self.left.get_indexer(other.left)
         rindexer = self.right.get_indexer(other.right)
@@ -1310,7 +1330,7 @@ def _intersection_non_unique(self, other: "IntervalIndex") -> "IntervalIndex":
 
         Returns
         -------
-        taken : IntervalIndex
+        IntervalIndex
         """
         mask = np.zeros(len(self), dtype=bool)
 
@@ -1360,7 +1380,9 @@ def is_all_dates(self) -> bool:
 
 
 def _is_valid_endpoint(endpoint) -> bool:
-    """helper for interval_range to check if start/end are valid types"""
+    """
+    Helper for interval_range to check if start/end are valid types.
+    """
     return any(
         [
             is_number(endpoint),
@@ -1372,7 +1394,9 @@ def _is_valid_endpoint(endpoint) -> bool:
 
 
 def _is_type_compatible(a, b) -> bool:
-    """helper for interval_range to check type compat of start/end/freq"""
+    """
+    Helper for interval_range to check type compat of start/end/freq.
+    """
     is_ts_compat = lambda x: isinstance(x, (Timestamp, DateOffset))
     is_td_compat = lambda x: isinstance(x, (Timedelta, DateOffset))
     return (
diff --git a/pandas/core/indexes/multi.py b/pandas/core/indexes/multi.py
index 9e434d0f5f704..d3b738e2a95d1 100644
--- a/pandas/core/indexes/multi.py
+++ b/pandas/core/indexes/multi.py
@@ -1,6 +1,7 @@
 from collections import OrderedDict
 import datetime
 from sys import getsizeof
+from typing import List, Optional
 import warnings
 
 import numpy as np
@@ -85,7 +86,7 @@ def _codes_to_ints(self, codes):
 
         Returns
         -------
-        int_keys : scalar or 1-dimensional array, of dtype uint64
+        scalar or 1-dimensional array, of dtype uint64
             Integer(s) representing one combination (each).
         """
         # Shift the representation of each level by the pre-calculated number
@@ -125,7 +126,7 @@ def _codes_to_ints(self, codes):
 
         Returns
         -------
-        int_keys : int, or 1-dimensional array of dtype object
+        int, or 1-dimensional array of dtype object
             Integer(s) representing one combination (each).
         """
 
@@ -248,8 +249,8 @@ def __new__(
         dtype=None,
         copy=False,
         name=None,
-        verify_integrity=True,
-        _set_identity=True,
+        verify_integrity: bool = True,
+        _set_identity: bool = True,
     ):
 
         # compat with Index
@@ -287,7 +288,7 @@ def __new__(
 
         return result
 
-    def _validate_codes(self, level: list, code: list):
+    def _validate_codes(self, level: List, code: List):
         """
         Reassign code values as -1 if their corresponding levels are NaN.
 
@@ -300,7 +301,7 @@ def _validate_codes(self, level: list, code: list):
 
         Returns
         -------
-        code : new code where code value = -1 if it corresponds
+        new code where code value = -1 if it corresponds
         to a level with missing values (NaN, NaT, None).
         """
         null_mask = isna(level)
@@ -308,9 +309,10 @@ def _validate_codes(self, level: list, code: list):
             code = np.where(null_mask[code], -1, code)
         return code
 
-    def _verify_integrity(self, codes=None, levels=None):
+    def _verify_integrity(
+        self, codes: Optional[List] = None, levels: Optional[List] = None
+    ):
         """
-
         Parameters
         ----------
         codes : optional list
@@ -326,7 +328,7 @@ def _verify_integrity(self, codes=None, levels=None):
 
         Returns
         -------
-        codes : new codes where code value = -1 if it corresponds to a
+        new codes where code value = -1 if it corresponds to a
         NaN level.
         """
         # NOTE: Currently does not check, among other things, that cached
@@ -336,8 +338,8 @@ def _verify_integrity(self, codes=None, levels=None):
 
         if len(levels) != len(codes):
             raise ValueError(
-                "Length of levels and codes must match. NOTE:"
-                " this index is in an inconsistent state."
+                "Length of levels and codes must match. NOTE: "
+                "this index is in an inconsistent state."
             )
         codes_length = len(codes[0])
         for i, (level, level_codes) in enumerate(zip(levels, codes)):
@@ -389,7 +391,7 @@ def from_arrays(cls, arrays, sortorder=None, names=_no_default_names):
 
         Returns
         -------
-        index : MultiIndex
+        MultiIndex
 
         See Also
         --------
@@ -454,7 +456,7 @@ def from_tuples(cls, tuples, sortorder=None, names=None):
 
         Returns
         -------
-        index : MultiIndex
+        MultiIndex
 
         See Also
         --------
@@ -481,8 +483,7 @@ def from_tuples(cls, tuples, sortorder=None, names=None):
 
         if len(tuples) == 0:
             if names is None:
-                msg = "Cannot infer number of levels from empty list"
-                raise TypeError(msg)
+                raise TypeError("Cannot infer number of levels from empty list")
             arrays = [[]] * len(names)
         elif isinstance(tuples, (np.ndarray, Index)):
             if isinstance(tuples, Index):
@@ -518,7 +519,7 @@ def from_product(cls, iterables, sortorder=None, names=_no_default_names):
 
         Returns
         -------
-        index : MultiIndex
+        MultiIndex
 
         See Also
         --------
@@ -653,15 +654,15 @@ def array(self):
         ------
         ValueError
         """
-        msg = (
+        raise ValueError(
             "MultiIndex has no single backing array. Use "
             "'MultiIndex.to_numpy()' to get a NumPy array of tuples."
         )
-        raise ValueError(msg)
 
     @property
     def _is_homogeneous_type(self) -> bool:
-        """Whether the levels of a MultiIndex all have the same dtype.
+        """
+        Whether the levels of a MultiIndex all have the same dtype.
 
         This looks at the dtypes of the levels.
 
@@ -732,7 +733,7 @@ def set_levels(self, levels, level=None, inplace=False, verify_integrity=True):
             Level(s) to set (None for all levels).
         inplace : bool
             If True, mutates in place.
-        verify_integrity : bool (default True)
+        verify_integrity : bool ,default True
             If True, checks that levels and codes are compatible.
 
         Returns
diff --git a/pandas/core/indexes/numeric.py b/pandas/core/indexes/numeric.py
index 048bff46759bc..b84c69b8caf51 100644
--- a/pandas/core/indexes/numeric.py
+++ b/pandas/core/indexes/numeric.py
@@ -85,8 +85,9 @@ def _validate_dtype(cls, dtype: Dtype) -> None:
 
         validation_func, expected = validation_metadata[cls._typ]
         if not validation_func(dtype):
-            msg = f"Incorrect `dtype` passed: expected {expected}, received {dtype}"
-            raise ValueError(msg)
+            raise ValueError(
+                f"Incorrect `dtype` passed: expected {expected}, received {dtype}"
+            )
 
     @Appender(_index_shared_docs["_maybe_cast_slice_bound"])
     def _maybe_cast_slice_bound(self, label, side, kind):
@@ -106,7 +107,6 @@ def _convert_for_op(self, value):
         """
         Convert value to be insertable to ndarray.
         """
-
         if is_bool(value) or is_bool_dtype(value):
             # force conversion to object
             # so we don't lose the bools
@@ -121,17 +121,13 @@ def _convert_tolerance(self, tolerance, target):
         if not np.issubdtype(tolerance.dtype, np.number):
             if tolerance.ndim > 0:
                 raise ValueError(
-                    (
-                        f"tolerance argument for {type(self).__name__} must contain "
-                        "numeric elements if it is list type"
-                    )
+                    f"tolerance argument for {type(self).__name__} must contain "
+                    "numeric elements if it is list type"
                 )
             else:
                 raise ValueError(
-                    (
-                        f"tolerance argument for {type(self).__name__} must be numeric "
-                        f"if it is a scalar: {repr(tolerance)}"
-                    )
+                    f"tolerance argument for {type(self).__name__} must be numeric "
+                    f"if it is a scalar: {repr(tolerance)}"
                 )
         return tolerance
 
@@ -244,7 +240,9 @@ class Int64Index(IntegerIndex):
 
     @property
     def inferred_type(self) -> str:
-        """Always 'integer' for ``Int64Index``"""
+        """
+        Always 'integer' for ``Int64Index``
+        """
         return "integer"
 
     @property
@@ -299,7 +297,9 @@ class UInt64Index(IntegerIndex):
 
     @property
     def inferred_type(self) -> str:
-        """Always 'integer' for ``UInt64Index``"""
+        """
+        Always 'integer' for ``UInt64Index``
+        """
         return "integer"
 
     @property
@@ -374,7 +374,9 @@ class Float64Index(NumericIndex):
 
     @property
     def inferred_type(self) -> str:
-        """Always 'floating' for ``Float64Index``"""
+        """
+        Always 'floating' for ``Float64Index``
+        """
         return "floating"
 
     @Appender(_index_shared_docs["astype"])
diff --git a/pandas/io/formats/console.py b/pandas/io/formats/console.py
index 1d4fa929b2138..bed29e1fd4792 100644
--- a/pandas/io/formats/console.py
+++ b/pandas/io/formats/console.py
@@ -6,7 +6,8 @@
 
 
 def get_console_size():
-    """Return console size as tuple = (width, height).
+    """
+    Return console size as tuple = (width, height).
 
     Returns (None,None) in non-interactive session.
     """
@@ -50,9 +51,13 @@ def get_console_size():
 
 
 def in_interactive_session():
-    """ check if we're running in an interactive shell
+    """
+    Check if we're running in an interactive shell.
 
-    returns True if running under python/ipython interactive shell
+    Returns
+    -------
+    bool
+        True if running under python/ipython interactive shell.
     """
     from pandas import get_option
 
@@ -71,7 +76,11 @@ def check_main():
 
 def in_ipython_frontend():
     """
-    check if we're inside an an IPython zmq frontend
+    Check if we're inside an an IPython zmq frontend.
+
+    Returns
+    -------
+    bool
     """
     try:
         ip = get_ipython()  # noqa

From adb088b5919f9450425c1b1170aa293ea3b0831f Mon Sep 17 00:00:00 2001
From: MomIsBestFriend <50263213+MomIsBestFriend@users.noreply.github.com>
Date: Sat, 21 Dec 2019 21:24:36 +0200
Subject: [PATCH 2/2] Update multi.py

---
 pandas/core/indexes/multi.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pandas/core/indexes/multi.py b/pandas/core/indexes/multi.py
index d3b738e2a95d1..05a4da28eb0a1 100644
--- a/pandas/core/indexes/multi.py
+++ b/pandas/core/indexes/multi.py
@@ -733,7 +733,7 @@ def set_levels(self, levels, level=None, inplace=False, verify_integrity=True):
             Level(s) to set (None for all levels).
         inplace : bool
             If True, mutates in place.
-        verify_integrity : bool ,default True
+        verify_integrity : bool, default True
             If True, checks that levels and codes are compatible.
 
         Returns