python – 如何在实例化时有条件地将mixin添加到当前类？

class MixinOne(object):
    def print_name(self):
        print("{} is using MixinOne.".format(self.name))


class MixinTwo(object):
    def print_name(self):
        print("{} is using MixinTwo.".format(self.name))


class Sub(object):

    def __new__(cls,*args,**kwargs):

        mixin = args[1]

        if mixin == 'one':
            bases = (MixinOne,) + cls.__bases__
        elif mixin == 'two':
            bases = (MixinTwo,) + cls.__bases__

        return object.__new__(type('Sub',bases,dict(cls.__dict__)))

    def __init__(self,name,mixin):

        print('In Sub.__init__')

        self.name = name

唯一的问题似乎是__init__没有被调用,所以print_name方法不起作用.

>如何让Sub上的__init__开火？

要么

>有更好的方法吗？