如何獲得在Python中工作的類繼承？

Question

我應該創建一個名爲Dog（Animal）的類，它繼承自Class Animal。不過之後我運行這段代碼，我得到了我不明白的錯誤：

問題是解決了，我此刻

class Animal: 
__name = "" 
__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 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 says{}".format(self.__name, 
                   self.__height, 
                   self.__weight, 
                   self.__sound) 


cat = Animal('pussy', 33, 10, 'meow') 
print(cat.toString()) 
print(cat.get_type()) 
print(cat.get_sound()) 

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") # Dog object 

def toString(self): 
    return "{} is {} cm tall and {} kilograms and says{} its owner is {}".format(self.__name, 
                       self.__height, 
                       self.__weight, 
                       self.__sound, 
                       self.__owner) 

spot = Dog("kaili", 22, 33, "woof", "Jiahui") 
print(spot.toString()) 

Answer 1

在我加入元類 =類型的開頭，問題就解決了。我不太清楚，但似乎metaclass允許python2.7訪問python3的庫。

Answer 2

改變這一行看到沒有進一步的問題：

class Animal: 

這樣：

class Animal(object): 

這post解釋了它相當不錯。