diff --git a/lightrag/kg/json_kv_impl.py b/lightrag/kg/json_kv_impl.py
index 54748a27..7e13dea7 100644
--- a/lightrag/kg/json_kv_impl.py
+++ b/lightrag/kg/json_kv_impl.py
@@ -49,4 +49,4 @@ class JsonKVStorage(BaseKVStorage):
     async def delete(self, ids: list[str]) -> None:
         for doc_id in ids:
             self._data.pop(doc_id, None)
-        await self.index_done_callback()
\ No newline at end of file
+        await self.index_done_callback()
diff --git a/lightrag/kg/mongo_impl.py b/lightrag/kg/mongo_impl.py
index 0e58e538..8cfc84b9 100644
--- a/lightrag/kg/mongo_impl.py
+++ b/lightrag/kg/mongo_impl.py
@@ -117,6 +117,7 @@ class MongoKVStorage(BaseKVStorage):
         # Mongo handles persistence automatically
         pass
 
+
 @final
 @dataclass
 class MongoDocStatusStorage(DocStatusStorage):
@@ -197,6 +198,7 @@ class MongoDocStatusStorage(DocStatusStorage):
         # Mongo handles persistence automatically
         pass
 
+
 @final
 @dataclass
 class MongoGraphStorage(BaseGraphStorage):
diff --git a/lightrag/kg/redis_impl.py b/lightrag/kg/redis_impl.py
index 3aa5c892..056fbc9e 100644
--- a/lightrag/kg/redis_impl.py
+++ b/lightrag/kg/redis_impl.py
@@ -60,4 +60,4 @@ class RedisKVStorage(BaseKVStorage):
 
     async def index_done_callback(self) -> None:
         # Redis handles persistence automatically
-        pass
\ No newline at end of file
+        pass