原型模式

class Prototype:
    def __init__(self):
        self.objects = {}

    def register(self, name, obj):
        self.objects[name]=obj

    def unregister(self, name):
        del self.objects[name]

    def clone(self, name, **kwargs):
        import copy
        obj = copy.deepcopy(self.objects.get(name))
        obj.__dict__.update(kwargs)
        return obj


class A:
    def __str__(self):
        return 'i am A'


def main():
    a = A()
    setattr(a,'e',10)
    prototype = Prototype()
    prototype.register('a', a)
    b = prototype.clone('a', e=1, f=2, g=3)
    print(a)
    print(a.e)
    print(b.e)
    print(b.f)
    print(b.g)
if __name__ == '__main__':
    main()