TST: use lists, reference GH issue

Author: ivanovmg

pandas/tests/frame/methods/test_sort_index.py

@@ -765,11 +765,12 @@ def test_sort_index_with_categories(self, categories):
         "ascending",
         [
             None,
-            (True, None),
-            (False, "True"),
+            [True, None],
+            [False, "True"],
         ],
     )
     def test_sort_index_ascending_bad_value_raises(self, ascending):
+        # GH 39434
         df = DataFrame(np.arange(64))
         length = len(df.index)
         df.index = [(i - length / 2) % length for i in range(length)]

pandas/util/_validators.py

@@ -2,7 +2,11 @@
 Module that contains many useful utilities
 for validating data or function arguments
 """
-from typing import Iterable, Sequence, Union
+from typing import (
+    Iterable,
+    Sequence,
+    Union,
+)
 import warnings
 
 import numpy as np