'''
多态,子类继承父类后可以重写父类方法
'''

from abc import ABCMeta, abstractmethod

class Animal(object, metaclass=ABCMeta):
 '''动物'''

 def __init__(self, nickname):
 self._nickname = nickname

 @abstractmethod
 def make_voice(self):
 '''发出声音'''
 pass

class Dog(Animal):
 '''狗'''
 def make_voice(self):
 print('%s:汪汪汪...' % self._nickname)

class Cat(Animal):
 '''猫'''
 def make_voice(self):
 print('%s:喵喵喵...' % self._nickname)

def main():
 pets = [Dog('旺财'), Cat('凯蒂'), Dog('大黄')]
 for pet in pets:
 pet.make_voice()

if __name__ == '__main__':
 main()