code: def set_error(self, error_shortmsg: str, error_longmsg: str):
          
          LOG.error(f"Update session: error in stage {self._stage.name}: "
                    f"{error_shortmsg}: {error_longmsg}")
          self._error = Value(error_shortmsg, error_longmsg)
          self.set_stage(Stages.ERROR)
docs: Set the stage to error and add a message