面向对象的三大特征:封装、继承、多态
class Base(object): def say(self): print('base....') class A(Base): def say(self): print('a....') class B(Base): def say(self): print('b...') def f(obj): obj.say() if __name__ == '__main__': a = A() b = B() base = Base() f(a) f(b) f(base) 结果: a.... b... base....