a method to report posix epoch timestamp from a labDT object

        :return: float with timestamp

def epoch(self):

        ''' a method to report posix epoch timestamp from a labDT object

        :return: float with timestamp
        '''

    # construct epoch timestamp from labDT
        epoch_dt = datetime.utcfromtimestamp(0).replace(tzinfo=pytz.utc)
        delta_time = self - epoch_dt
        return delta_time.total_seconds()