fixes mypy

fastapi_async_sqlalchemy/middleware.py

@@ -67,7 +67,7 @@ def session(self) -> AsyncSession:
 
             multi_sessions = _multi_sessions_ctx.get()
             if multi_sessions:
-                """ In this case, we need to create a new session for each task.
+                """In this case, we need to create a new session for each task.
                 We also need to commit the session on exit if commit_on_exit is True.
                 This is useful when we need to run multiple queries in parallel.
                 For example, when we need to run multiple queries in parallel in a route handler.