diff --git a/libs/checkpoint-postgres/langgraph/checkpoint/postgres/base.py b/libs/checkpoint-postgres/langgraph/checkpoint/postgres/base.py
index 121042954..fd868568d 100644
--- a/libs/checkpoint-postgres/langgraph/checkpoint/postgres/base.py
+++ b/libs/checkpoint-postgres/langgraph/checkpoint/postgres/base.py
@@ -357,9 +357,9 @@ class BasePostgresSaver(BaseCheckpointSaver[str]):
         a `_ChannelWritesHistory` per requested channel.
         """
         # writes_by_ch_by_cid[channel][cid] = list of (type, blob, task_id, idx)
-        writes_by_ch_by_cid: dict[
-            str, dict[str, list[tuple[str, bytes, str, int]]]
-        ] = {ch: {} for ch in channels}
+        writes_by_ch_by_cid: dict[str, dict[str, list[tuple[str, bytes, str, int]]]] = {
+            ch: {} for ch in channels
+        }
         # seed_blob_by_ver[(channel, version)] = (type, blob)
         seed_blob_by_ver: dict[tuple[str, str], tuple[str, bytes]] = {}
 
diff --git a/libs/checkpoint/langgraph/checkpoint/memory/__init__.py b/libs/checkpoint/langgraph/checkpoint/memory/__init__.py
index 11f35b0a5..c74f2f118 100644
--- a/libs/checkpoint/langgraph/checkpoint/memory/__init__.py
+++ b/libs/checkpoint/langgraph/checkpoint/memory/__init__.py
@@ -189,9 +189,7 @@ class InMemorySaver(
                     ver = versions.get(ch)
                     if ver is None:
                         continue
-                    blob_entry = self.blobs.get(
-                        (thread_id, checkpoint_ns, ch, ver)
-                    )
+                    blob_entry = self.blobs.get((thread_id, checkpoint_ns, ch, ver))
                     if blob_entry is None or blob_entry[0] == "empty":
                         continue
                     blob_value = self.serde.loads_typed(blob_entry)
diff --git a/libs/checkpoint/tests/test_memory.py b/libs/checkpoint/tests/test_memory.py
index 369ca65cd..fccc09705 100644
--- a/libs/checkpoint/tests/test_memory.py
+++ b/libs/checkpoint/tests/test_memory.py
@@ -482,9 +482,9 @@ class TestBaseFallbackGetChannelWrites:
             }
         }
 
-        result = saver._get_all_delta_channels_writes_history(
-            config, ["messages"]
-        )["messages"]
+        result = saver._get_all_delta_channels_writes_history(config, ["messages"])[
+            "messages"
+        ]
 
         assert result.seed is DELTA_SENTINEL
         values = [v for _, _, v in result.writes]
diff --git a/libs/langgraph/langgraph/pregel/_checkpoint.py b/libs/langgraph/langgraph/pregel/_checkpoint.py
index 715b5df1f..951bdfcf9 100644
--- a/libs/langgraph/langgraph/pregel/_checkpoint.py
+++ b/libs/langgraph/langgraph/pregel/_checkpoint.py
@@ -136,9 +136,7 @@ def channels_from_checkpoint(
     ]
     histories: Mapping[str, Any] = {}
     if delta_channels and saver is not None and config is not None:
-        histories = saver._get_all_delta_channels_writes_history(
-            config, delta_channels
-        )
+        histories = saver._get_all_delta_channels_writes_history(config, delta_channels)
 
     channels: dict[str, BaseChannel] = {}
     for k, spec in channel_specs.items():