fix model_class if model_name is not set
@@ -384,7 +384,7 @@ class Change(models.Model):
@property
def model_class(self) -> typing.Optional[typing.Type[models.Model]]:
- if self.model_name is None:
+ if not self.model_name:
return None
return apps.get_model('mapdata', self.model_name)
