docs: def from_json(self, txt, **kwargs):
          """
          Convert from a JSON string to an instance of this class.
          
          :param txt: The JSON string (a ``str``, ``bytes`` or ``bytearray``
              instance containing a JSON document)
          :param kwargs: extra keyword arguments
          :return: The instantiated instance 
          """
          _dict = json.loads(txt)
          return self.from_dict(_dict)