docs: def log(self, user, content, message):
          """creates a new log record
  
          :param user: user
          :param content: content instance
          :param message: change information
          """
          return self.create(
              user=user,
              content_type=ContentType.objects.get_for_model(content),
              object_id=content.pk,
              change_message=message
          )