def next_month(arg=_date, clean=False):
    _arg = _datetime_to_date(arg)
    this_month_last_day = lastday(_arg.year, _arg.month)
    next_month_first_day = this_month_last_day + _ONE_DAY
    next_month_last_day = lastday(next_month_first_day.year, next_month_first_day.month)
    return next_month_first_day, next_month_last_day if clean else next_month_last_day / _ONE_DAY


######################
# festival
######################
dataset/ETHPy150Open shinux/PyTime/pytime/pytime.py/next_month/operator `+` -> `/`