def _get_start_from_job(job):
        """
        :param: fedlearner_webconsole.job.models.Job
        :return: An iso format datetime string in UTC
        """
        if job.created_at.tzinfo:
            start = pytz.utc.normalize(job.created_at)
        else:
            start = pytz.utc.normalize(Envs.TZ.localize(job.created_at))
        # e.g., 2021-01-01T12:00:00Z, which is equivalent to 20:00:00 on the
        # same day in UTC+08:00 (BJT)
        start = start.isoformat(timespec='seconds')[:-6] + 'Z'
        return start

        :param: fedlearner_webconsole.job.models.Job
        :return: An iso format datetime string in UTC
        
web_console_v2/api/fedlearner_webconsole/utils/kibana.py