diff --git a/django_migration_linter/sql_analyser/postgresql.py b/django_migration_linter/sql_analyser/postgresql.py
index 2f8608c..1d64fd2 100644
--- a/django_migration_linter/sql_analyser/postgresql.py
+++ b/django_migration_linter/sql_analyser/postgresql.py
@@ -15,7 +15,8 @@ class PostgresqlAnalyser(BaseAnalyser):
         },
         {
             "code": "DROP_INDEX",
-            "fn": lambda sql, **kw: re.search("DROP INDEX", sql) and not re.search("INDEX CONCURRENTLY", sql),
+            "fn": lambda sql, **kw: re.search("DROP INDEX", sql)
+            and not re.search("INDEX CONCURRENTLY", sql),
             "msg": "DROP INDEX locks table",
             "mode": "one_liner",
             "type": "warning",
diff --git a/tests/unit/test_sql_analyser.py b/tests/unit/test_sql_analyser.py
index a810aef..5b7e590 100644
--- a/tests/unit/test_sql_analyser.py
+++ b/tests/unit/test_sql_analyser.py
@@ -17,7 +17,9 @@ class SqlAnalyserTestCase(unittest.TestCase):
         errors, _, warnings = self.analyse_sql(sql)
         self.assertEqual(0, len(errors), "Found errors in sql: {}".format(errors))
         if not allow_warnings:
-            self.assertEqual(0, len(warnings), "Found warnings in sql: {}".format(errors))
+            self.assertEqual(
+                0, len(warnings), "Found warnings in sql: {}".format(errors)
+            )
 
     def assertBackwardIncompatibleSql(self, sql):
         errors, _, _ = self.analyse_sql(sql)