def getGpsTime(dt):
    """_getGpsTime returns gps time (seconds since midnight Sat/Sun) for a datetime
    """
    total = 0
    days = (dt.weekday()+ 1) % 7 # this makes Sunday = 0, Monday = 1, etc.
    total += days*3600*24
    total += dt.hour * 3600
    total += dt.minute * 60
    total += dt.second
    return(total)