CLN: changed type hints to fix mypy errors

Author: jacobaustin123

pandas/core/indexes/base.py

@@ -4524,7 +4524,7 @@ def asof_locs(self, where, mask):
 
         return result
 
-    def sort_values(self, return_indexer=False, ascending=True, key : Union[Callable, None] = None):
+    def sort_values(self, return_indexer=False, ascending=True, key : Callable = None):
         """
         Return a sorted copy of the index.
 
@@ -4537,8 +4537,9 @@ def sort_values(self, return_indexer=False, ascending=True, key : Union[Callable
             Should the indices that would sort the index be returned.
         ascending : bool, default True
             Should the index values be sorted in an ascending order.
-        key : Union[Callable, None] , default None
-            Apply a key function to the indices before sorting, like sorted.
+        key : Callable, default None
+            Apply a key function to the indices before sorting, like 
+            built-in sorted function.
 
         Returns
         -------

pandas/core/series.py

@@ -3019,7 +3019,7 @@ def sort_values(
         inplace=False,
         kind="quicksort",
         na_position="last",
-        key: Union[Callable, None] = None
+        key: Callable = None
     ):
         """
         Sort by the values.
@@ -3042,7 +3042,7 @@ def sort_values(
         na_position : {'first' or 'last'}, default 'last'
             Argument 'first' puts NaNs at the beginning, 'last' puts NaNs at
             the end.
-        key : Union[Callable, None], default None
+        key : Callable, default None
             If not None, apply the key function to every value before
             sorting. Identical to key argument in built-in sorted function.
 
@@ -3220,7 +3220,7 @@ def sort_index(
         kind="quicksort",
         na_position="last",
         sort_remaining=True,
-        key : Union[Callable, None] = None
+        key : Callable = None
     ):
         """
         Sort Series by index labels.
@@ -3249,7 +3249,7 @@ def sort_index(
         sort_remaining : bool, default True
             If True and sorting by level and index is multilevel, sort by other
             levels too (in order) after sorting by specified level.
-        key : Union[Callable, None], default None
+        key : Callable, default None
             If not None, apply the key function to every index element before
             sorting. Identical to key argument in built-in sorted function.
 

pandas/core/sorting.py

@@ -202,7 +202,7 @@ def lexsort_indexer(keys, orders=None, na_position="last", key : Union[Callable,
 
     if key:
         key_func = np.vectorize(key)
-        keys = [key_func(key) if key.size != 0 else key for key in keys]
+        keys = [key_func(entry) if entry.size != 0 else entry for entry in keys]
 
     for key, order in zip(keys, orders):
 

pandas/tests/frame/test_sorting.py

@@ -652,7 +652,7 @@ def test_sort_value_key_nan(self):
     @pytest.mark.parametrize('key', [None, lambda x : x])
     def test_sort_value_key_empty(self, key):
         df = DataFrame(np.array([]))
-        
+ 
         df.sort_values(0, key=key)
         df.sort_index(key=key)