prog11_13.py

class Cat:
    VOICE = "ニャー"
    _cats = []

    def __init__(self, name):
        self.name = name
        self.__class__._cats.append(self)

    def talk(self):
        print(f"{self.name}「{self.__class__.VOICE}」")

    @classmethod
    def parade(cls):
        for cat in cls._cats:
            cat.talk()

c1 = Cat("そら")
c2 = Cat("テト")
c3 = Cat("ミミ")
Cat.parade()

# プログラム11-13（クラスメソッド ①：猫をすべて鳴かせる）