Incorporate review suggestion for issue #63178

 BUG: Inconsistent behavior of Groupby with None values with filter

Author: T. Koskamp

pandas/core/groupby/groupby.py

@@ -636,7 +636,7 @@ def indices(self) -> dict[Hashable, npt.NDArray[np.intp]]:
         return self._grouper.indices
 
     @final
-    def _get_indices(self, name):
+    def _get_index(self, name):
         """
         Safe get multiple indices, translate keys for
         datelike to underlying repr.
@@ -686,13 +686,6 @@ def get_converter(s):
 
         return self.indices.get(name, [])
 
-    @final
-    def _get_index(self, name):
-        """
-        Safe get index, translate keys for datelike to underlying repr.
-        """
-        return self._get_indices(name)
-
     @final
     @cache_readonly
     def _selected_obj(self):

pandas/core/groupby/ops.py

@@ -665,7 +665,8 @@ def indices(self) -> dict[Hashable, npt.NDArray[np.intp]]:
             elif has_mi:
                 # MultiIndex has no efficient way to tell if there are NAs
                 result = {
-                    tuple(np.nan if isna(comp) else comp for comp in key): value
+                    # error: "Hashable" has no attribute "__iter__" (not iterable)
+                    tuple(np.nan if isna(comp) else comp for comp in key): value  # type: ignore[attr-defined]
                     for key, value in result.items()
                 }