diff --git a/rhodecode/lib/dbmigrate/migrate/exceptions.py b/rhodecode/lib/dbmigrate/migrate/exceptions.py
--- a/rhodecode/lib/dbmigrate/migrate/exceptions.py
+++ b/rhodecode/lib/dbmigrate/migrate/exceptions.py
@@ -83,5 +83,6 @@ class NotSupportedError(Error):
 class InvalidConstraintError(Error):
     """Invalid constraint error"""
 
+
 class MigrateDeprecationWarning(DeprecationWarning):
     """Warning for deprecated features in Migrate"""