class Time(object):    def __init__(self, hr, min):        self.hr = hr        self.min = min    def __str__(self):        return '%d:%d' %(self.hr, self.min)    __repr__ = __str__    # 重载加法    def __add__(self, other):        m = self.min + other.min        h = self.hr + other.hr        if m>=60:            m -= 60            h += 1        if h>=24:            h -= 24        return self.__class__(h, m)    # 重载'+='方法    def __iadd__(self, other):        self.hr += other.hr        self.min += other.min        if self.min >= 60:            self.min -= 60            self.hr += 1        if self.hr >=24:            self.hr -= 24        return self

这样就能实现时间的加法。

>> a=Time(3, 6)>> b=Time(20, 52)>> a3:6>> a+b23:58>> a+=b>>a23:58