# ------------------------------- # Difficult Rocket # Copyright © 2021-2022 by shenjackyuanjie # All rights reserved # ------------------------------- """ writen by shenjackyuanjie mail: 3695888@qq.com github: @shenjackyuanjie gitee: @shenjackyuanjie """ class Units: """ base class of all units """ def __init__(self): pass class _Newton(Units): pass newton = _Newton() class _Metre(Units): pass metre = _Metre() class _Second(Units): pass second = _Second()