A类添加B类报错

FavouritePython

class A:
    def get_a(slef):
        print('a')
class B:
    def get_b(self):
        print('b')



A.__bases__ +=(B,)
Traceback (most recent call last):
  File "<pyshell#25>", line 1, in <module>
    A.__bases__ +=(B,)
TypeError: Cannot create a consistent method resolution
order (MRO) for bases object, B
什么鬼。为什么我实现不了这个功能