python 多继承 mro问题

class Parent(object):
    def __init__(self, name, *args, **kwargs):
        print('parent start')
        self.name = name
        print('parent end')


class Son1(Parent):
    def __init__(self, name, age, *args, **kwargs):
        print('son1 start')
        self.age = age
        # Parent.__init__(self,name)
        super().__init__(name,*args,**kwargs)
        # super(Parent,self).__init__()
        print('Son1 end')


class Son2(Parent):
    def __init__(self, name, gender, *args, **kwargs):
        print('son2 start')
        self.gender = gender
        # Parent.__init__(self,name)
        super().__init__(name,*args,**kwargs)
        # super(Parent,self).__init__()
        print('Son2 end')


class GrandSon(Son1, Son2):
    def __init__(self, name, age, gender, *args, **kwargs):
        super().__init__(name, age, gender)
        print('grand')


grand = GrandSon('zs', 30, 'male')

print(GrandSon.__mro__)