'Returns a DateTime object that represents the timestamp of the most recent
queueing request, or None if not queued'

def get_recentmost_queuetime(self):

    if (not self.is_queued()):
        return None
    queuetime_strs = [self.correct_map.get_queuetime_str(answer_id) for answer_id in self.correct_map if self.correct_map.is_queued(answer_id)]
    queuetimes = [datetime.strptime(qt_str, xqueue_interface.dateformat).replace(tzinfo=UTC) for qt_str in queuetime_strs]
    return max(queuetimes)
