class A(object):
    def __init__(self,a):
        print ('init A...')
        self.a = a
        print (self.a)
class C(A):
    def __init__(self,a,b,c):
        super().__init__(a)
        self.b=b
        self.c=c
        print ('init C...')
        print (self.b)
        print (self.c)
class B(A):
    def __init__(self,a,b):
        super().__init__(a)
        self.b=b
        print ('init B...')
        print (self.c)

class D(C,B):
    def __init__(self, a,b,c,d):
        super().__init__(a,b,c)
        
        #C.__init__(a,b,c)
        #B.__init__(d)
        self.c=c
        self.b=b
        print ('init D...')

p1=D('a','b','c','d')