diff --git a/libs/checkpoint-postgres/langgraph/checkpoint/postgres/aio.py b/libs/checkpoint-postgres/langgraph/checkpoint/postgres/aio.py
index a931181e1..6140af756 100644
--- a/libs/checkpoint-postgres/langgraph/checkpoint/postgres/aio.py
+++ b/libs/checkpoint-postgres/langgraph/checkpoint/postgres/aio.py
@@ -333,7 +333,7 @@ class AsyncPostgresSaver(BasePostgresSaver):
 
     def list(
         self,
-        config: RunnableConfig | None,
+        config: Optional[RunnableConfig],
         *,
         filter: Optional[dict[str, Any]] = None,
         before: Optional[RunnableConfig] = None,