docs: def ReadCronJobRun(self, job_id, run_id):
      """Reads a single cron job run from the db."""
      for run in itervalues(self.cronjob_runs):
        if run.cron_job_id == job_id and run.run_id == run_id:
          return run
      raise db.UnknownCronJobRunError(
          "Run with job id %s and run id %s not found." % (job_id, run_id))