class PetCat():
    """  家猫类"""

    def __init__(self, name, age):
        self.name = name
        # 私有属性
        self.__age = age

    @property
    def age(self):
        return self.__age

    @age.setter
    def age(self,value):
        if not isinstance(value, int):
            print('年龄只能是整数')
            return 0
        if value < 0 or value > 100:
            print('年龄只能介于0-100之间')
            return 0
        self.__age = value

    # 描述符
    @property
    def show_info(self):
        return "我叫{0},今年{1}岁".format(self.name,self.age)

    def __str__(self):
        # return self.show_info()
        return '---'

if __name__ == '__main__':
   cat_black = PetCat('小黑', 2)
   rest = cat_black.show_info
   print(rest)
   # print('-------------')
   # print(cat_black)  #我叫小黑,今年2岁
   cat_black.age = 6
   rest = cat_black.show_info
   print(rest)