Update env.py

backend/alembic/env.py

@@ -1,7 +1,7 @@
 import logging
 from alembic import context
 from oasst_backend import models  # noqa: F401
-from sqlalchemy import engine_from_config, pool
+from sqlalchemy import (engine_from_config,pool)
 
 # Read in the Alembic config file.
 config = context.config