python抽象类定义，python抽象定义,class Animal

python抽象类定义，python抽象定义,class Animal

class Animal:    def reply(self):          self.speak()            def speak(self):          print 'spam'        class Mammal(Animal):    def speak(self):         print 'speak?'class Cat(Mammal):    def speak(self):          print 'Speak from Cat'class Dog(Mammal):    def speak(self):          print 'Speak from Dog'class Primate(Mammal):    def speak(self):          print 'Speak from primate!'class Hacker(Primate): pass     if __name__ == '__main__':    spot = Cat()    spot.reply()            data = Hacker()         data.reply()