class Animal:
    pass


class Mammal(Animal):#哺乳类
    pass


class Bird(Animal):#鸟类
    pass



class Dog(Mammal): #狗类
    pass


class Parrort(Bird): #鹦鹉类
    pass



class Runnable:  #跑类
    def run(self):
        print(‘running...‘)


class Flyable:  #分类
    def fly(self):
        print(‘flying...‘)


#多继承开始了，注意高能预警
class Dog(Mammal, Runnable):
    pass

class Parrot(Bird, Flyable):
    pass