经典类深度优先，新式类是广度优先

#深度优先和广度优先
#新式类基本都是广度优先
class A:#如果没有具体继承类默认继承类是object
    def test(self):
        print('A')
class B(A):
    pass
    # def test(self):
    #     print('B')
class C(A):
   pass
    # def test(self):
    #     print('C')
class D(B):
    # def test(self):
    #     print('D')
    pass
class E(C):
    # def test(self):
    #     print('E')
    pass
class F(D,E):#新式类从左往右
    #F-D-B不找A,然后回到右边从E-C-A---object
    # def test(self):
    #     print('F')
    pass
f1=F()
f1.test()
print(F.mro())#mro列表F-D-B不找A,然后回到右边从E-C-A---object