__new__ 实例化子类

class Foo(object):
    def __init__(self, name):
        self.name = name
        print "======================================"
        super(Foo, self).__init__()

    def __new__(cls, *args, **kwargs):
        return super(Foo, cls).__new__(Bar)

    def func1(self):
        print "111111111111111111111"*10

    def func2(self):
        print "222222222222222222222"*10
        self.func3();

class Bar(Foo):
    def __init__(self, *args, **kwargs):
        import pdb; pdb.set_trace();
        print args
        print kwargs

    def __new__(cls, *args, **kwargs):
        import pdb; pdb.set_trace();
        super(Bar, cls).__new__(*args, **kwargs)

    def func3(self):
        print "333333333333333333333"

    def func4(self):
        self.func1();
        print "444444444444444444444"


if __name__ == '__main__':
    import pdb; pdb.set_trace();
    f = Foo()
    f.func2()
    f.func3()
    f.func4()