docs: def ResolveCronJobFlowURN(self, cron_job_id):
      """Resolve a URN of a flow with this id belonging to a given cron job."""
      if not self._value:
        raise ValueError("Can't call ResolveCronJobFlowURN on an empty "
                         "client id.")
  
      return cron_job_id.ToURN().Add(self._value)