docs: def _from_dict(cls, _dict):
          """Initialize a KeyValuePair object from a json dictionary."""
          args = {}
          if 'key' in _dict:
              args['key'] = Key._from_dict(_dict.get('key'))
          if 'value' in _dict:
              args['value'] = Value._from_dict(_dict.get('value'))
          return cls(**args)