Fixed linter issue.

Author: Simon Prickett

aredis_om/model/migrations/migrator.py

@@ -41,7 +41,7 @@ def schema_hash_key(index_name):
 
 async def create_index(redis: Redis, index_name, schema, current_hash):
     db_number = redis.connection_pool.connection_kwargs.get("db")
-    if  db_number and db_number > 0:
+    if db_number and db_number > 0:
         raise MigrationError(
             "Creating search indexes is only supported in database 0. "
             f"You attempted to create an index in database {db_number}"