diff --git a/aerich/migrate.py b/aerich/migrate.py
index 27fba58..bedea8d 100644
--- a/aerich/migrate.py
+++ b/aerich/migrate.py
@@ -153,14 +153,15 @@ class Migrate:
         """
         builds content for diff file from template
         """
+
         def join_lines(lines: List[str]) -> str:
             if not lines:
                 return ""
             return ";\n        ".join(lines) + ";"
-            
+
         return MIGRATE_TEMPLATE.format(
-            upgrade_sql=join_lines(cls.upgrade_operators), 
-            downgrade_sql=join_lines(cls.downgrade_operators)
+            upgrade_sql=join_lines(cls.upgrade_operators),
+            downgrade_sql=join_lines(cls.downgrade_operators),
         )
 
     @classmethod
diff --git a/tests/test_migrate.py b/tests/test_migrate.py
index a94d73f..9269376 100644
--- a/tests/test_migrate.py
+++ b/tests/test_migrate.py
@@ -970,6 +970,7 @@ def test_sort_all_version_files(mocker):
         "11_datetime_update.py",
     ]
 
+
 async def test_empty_migration(mocker) -> None:
     mocker.patch("os.listdir", return_value=[])
     Migrate.app = "foo"