Resolve a URN of a flow with this id belonging to a given cron job.

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)