当我在PyCharm中运行这个程序时，我得到以下错误

当我运行这段代码时，我得到了以下错误：\n

\nTraceback (most recent call last): File \"C:/Users/Nabeel Hussain Syed/PycharmProjects/Hello World/check.py\", line 80, in \n print(spot.toString())\n File \"C:/Users/Nabeel Hussain Syed/PycharmProjects/Hello World/check.py\", line 66, in toString\n return \"{} is {} cm tall and {} kilograms and say {}. His owner is {}\".format(self.__name,\n AttributeError: \'Dog\' object has no attribute \'_Dog__name\'\n

\n打开图片链接查看错误。\n

    class Animal:
    __name = None
    __height = 0
    __weight = 0
    __sound = 0
    def __init__(self, name, height, weight, sound):
        self.__name = name
        self.__height = height
        self.__weight = weight
        self.__sound = sound
    def set_name(self, name):
        self.__name = name
    def set_height(self, height):
        self.__height = height
    def set_weight(self, weight):
        self.__weight = weight
    def set_sound(self, sound):
        self.__sound = sound
    def get_name(self):
        return self.__name
    def get_height(self):
        return str(self.__height)
    def get_weight(self):
        return str(self.__weight)
    def get_sound(self):
        return self.__sound
    def get_type(self):
        print("Animal")
    def toString(self):
        return "{} is {} cm tall and {} kilograms and say {}".format(self.__name,
                                                            self.__height,
                                                            self.__weight,
                                                            self.__sound)
cat = Animal('Whiskers', 33, 10, 'Meow')
print(cat.toString())
class Dog(Animal):
    __owner = ""
    def __init__(self,name,height,weight,sound,owner):
        self.__owner = owner
        super(Dog,self).__init__(name,height,weight,sound)
    def set_owner(self, owner):
        self.__owner = owner
    def get_owner(self):
        return self.__owner
    def get_type(self):
        print("Dog")
    def toString(self):
        return "{} is {} cm tall and {} kilograms and say {}. His owner is {}".format(self.__name,
                                                            self.__height,
                                                            self.__weight,
                                                            self.__sound,
                                                            self.__owner)
    def multiple_sounds(self, how_many=None):
        if how_many is None:
            print(self.get_sound())
        else:
            print(self.get_sound() * how_many)
spot = Dog("Spot", 53, 27, "Ruff", "Derek")
print(spot.toString())