code: def _validate_api_root(self):
          
          if not self._title:
              msg = "No 'title' in API Root for request '{}'"
              raise ValidationError(msg.format(self.url))
  
          if not self._versions:
              msg = "No 'versions' in API Root for request '{}'"
              raise ValidationError(msg.format(self.url))
  
          if self._max_content_length is None:
              msg = "No 'max_content_length' in API Root for request '{}'"
              raise ValidationError(msg.format(self.url))
docs: Validates API Root information. Raises errors for required
          properties.