10.02经典类的bug

#以下在python 3.6版本里已没有这个问题了
1class A:
    def _init__(self):
        print ("this is A")
    def save(self):
        print ("save metho from A")

class B(A):
    def _init__(self):
        print ("this is B")

class C(A):
    def _init__(self):
        print ("this is C")
    def save(self):
        print ("save metho from C")

class D(B,C):
    def _init__(self):
        print ("this is D")

D1 = D()
D1.save()    #旧的python版本里会显示为"save metho from A",python 3.0开始，没有旧式（经典）类了，也已修改了这个bug