docs: def from_json(cls, jsonmsg):
          """ Create an object directly from a JSON string.
  
          Applies general validation after creating the
          object to check whether all required fields are
          present.
  
          Args:
              jsonmsg (str): An object encoded as a JSON string
  
          Returns:
              An object of the generated type
  
          Raises:
              ValidationError: if `jsonmsg` does not match the schema
                  `cls` was generated from
          """
          import json
          msg = json.loads(jsonmsg)
          obj = cls(**msg)
          obj.validate()
          return obj