mypy fixup

Author: jbrockmendel

pandas/core/arrays/_arrow_string_mixins.py

@@ -3,6 +3,7 @@
 from functools import partial
 from typing import (
     TYPE_CHECKING,
+    Any,
     Literal,
 )
 
@@ -20,7 +21,10 @@
     import pyarrow.compute as pc
 
 if TYPE_CHECKING:
-    from collections.abc import Sized
+    from collections.abc import (
+        Callable,
+        Sized,
+    )
 
     from pandas._typing import (
         Scalar,
@@ -42,6 +46,9 @@ def _convert_int_result(self, result):
         # Convert an integer-dtype result to the appropriate result type
         raise NotImplementedError
 
+    def _apply_elementwise(self, func: Callable) -> list[list[Any]]:
+        raise NotImplementedError
+
     def _str_pad(
         self,
         width: int,