diff --git a/libs/checkpoint/langgraph/checkpoint/memory/__init__.py b/libs/checkpoint/langgraph/checkpoint/memory/__init__.py
index dee64a327..6918de87a 100644
--- a/libs/checkpoint/langgraph/checkpoint/memory/__init__.py
+++ b/libs/checkpoint/langgraph/checkpoint/memory/__init__.py
@@ -177,7 +177,9 @@ class MemorySaver(
             Iterator[CheckpointTuple]: An iterator of matching checkpoint tuples.
         """
         thread_ids = (config["configurable"]["thread_id"],) if config else self.storage
-        config_checkpoint_ns = config["configurable"].get("checkpoint_ns") if config else None
+        config_checkpoint_ns = (
+            config["configurable"].get("checkpoint_ns") if config else None
+        )
         config_checkpoint_id = get_checkpoint_id(config) if config else None
         for thread_id in thread_ids:
             for checkpoint_ns in self.storage[thread_id].keys():