docs: def _to_dict(self):
          """Return a json dictionary representing this model."""
          _dict = {}
          if hasattr(self,
                     'images_processed') and self.images_processed is not None:
              _dict['images_processed'] = self.images_processed
          if hasattr(self, 'images') and self.images is not None:
              _dict['images'] = [x._to_dict() for x in self.images]
          if hasattr(self, 'warnings') and self.warnings is not None:
              _dict['warnings'] = [x._to_dict() for x in self.warnings]
          return _dict