菱形继承

#菱形继承
# class A():
#     def __init__(self):
#         print('A开始')
#         print('A结束')
# class B():
#     def __init__(self):
#         print('B开始')
#         super().__init__()
#         print('B结束')
# class C(A):
#     def __init__(self):
#         print('C开始')
#         super().__init__()
#         print('C结束')
# class D(C,B):
#     def __init__(self):
#         print('D开始')
#         super().__init__()
#         print('D结束')
# d=D()
# print(D.mro())