def U(self):
        if isinstance(self.data, datetime.datetime) and is_aware(self.data):
            return int(calendar.timegm(self.data.utctimetuple()))
        else:
            return int(time.mktime(self.data.timetuple()))
Seconds since the Unix epoch (January 1 1970 00:00:00 GMT)
dataset/ETHPy150Open django/django/django/utils/dateformat.py/DateFormat.U