docs: def _from_dict(cls, _dict):
          """Initialize a MessageResponse object from a json dictionary."""
          args = {}
          if 'output' in _dict:
              args['output'] = MessageOutput._from_dict(_dict.get('output'))
          else:
              raise ValueError(
                  'Required property \'output\' not present in MessageResponse JSON'
              )
          if 'context' in _dict:
              args['context'] = MessageContext._from_dict(_dict.get('context'))
          return cls(**args)