add type variable for DataSplitter

Author: simonjayhawkins

pandas/core/groupby/ops.py

@@ -124,7 +124,9 @@ def get_iterator(self, data: FrameOrSeries, axis: int = 0):
         for key, (i, group) in zip(keys, splitter):
             yield key, group
 
-    def _get_splitter(self, data: FrameOrSeries, axis: int = 0) -> "DataSplitter":
+    def _get_splitter(
+        self, data: FrameOrSeries, axis: int = 0
+    ) -> "DataSplitter[FrameOrSeries]":
         comp_ids, _, ngroups = self.group_info
         return get_splitter(data, comp_ids, ngroups, axis=axis)