diff --git a/libs/langgraph/tests/test_pregel_async.py b/libs/langgraph/tests/test_pregel_async.py
index bb8d4ff25..63a2f75f7 100644
--- a/libs/langgraph/tests/test_pregel_async.py
+++ b/libs/langgraph/tests/test_pregel_async.py
@@ -9871,7 +9871,7 @@ async def test_debug_subgraphs():
 
     assert len(checkpoint_events) == len(checkpoint_history)
 
-    def normalize_config(config: dict | None) -> dict | None:
+    def normalize_config(config: Optional[dict, None]) -> Optional[dict, None]:
         if config is None:
             return None
         return config["configurable"]