Add key type

Author: howsiwei

pandas/core/indexing.py

@@ -1,5 +1,5 @@
 import textwrap
-from typing import Tuple
+from typing import Iterable, Tuple
 import warnings
 
 import numpy as np
@@ -1811,7 +1811,7 @@ def _getitem_axis(self, key, axis: int):
         self._validate_key(key, axis)
         return self._get_label(key, axis=axis)
 
-    def _ensure_listlike_indexer(self, key, axis: int):
+    def _ensure_listlike_indexer(self, key: Iterable, axis: int):
         """
         Ensure that a list-like of keys are all present by adding them if they
         do not already exist.
@@ -1842,6 +1842,7 @@ def _get_setitem_indexer(self, key):
             self._ensure_listlike_indexer(key[1], axis=1)
         return super()._get_setitem_indexer(key)
 
+
 class _iLocIndexer(_LocationIndexer):
     """
     Purely integer-location based indexing for selection by position.