[ Python 常見問題 ] python multiple inheritance passing arguments to constructors using super

Source From Here 
Question 
Consider the following snippet of python code: 

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1. class A(object):  
2.     def __init__(self, a):  
3.         self.a = a  
4.   
5. class B(A):  
6.     def __init__(self, a, b):  
7.         super(B, self).__init__(a)  
8.         self.b = b  
9.   
10. class C(A):  
11.     def __init__(self, a, c):  
12.         super(C, self).__init__(a)  
13.         self.c = c  
14.   
15. class D(B, C):  
16.     def __init__(self, a, b, c, d):  
17.         #super(D,self).__init__(a, b, c) ???  
18.         self.d = d  

I am wondering how can I pass a, b and c to corresponding base classes' constructors. 

How-To 
Well, when dealing with multiple inheritance in general, your base classes (unfortunately) should be designed for multiple inheritance. Classes B and C in your example aren't, and thus you couldn't find a proper way to apply super in D. 

One of the common ways of designing your base classes for multiple inheritance, is for the middle-level base classes to accept extra args in their __init__ method, which they are not intending to use, and pass them along to their super call. 

Here's one way to do it in python: 

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1. class A(object):  
2.     def __init__(self, a):  
3.         self.a = a  
4.           
5.     def showA(self):  
6.         print("A.a={}".format(self.a))  
7.       
8. class B(A):  
9.     def __init__(self, b, **kw):  
10.         self.b=b  
11.         super(B, self).__init__(**kw)  
12.           
13.     def showB(self):  
14.         print("B.b={}".format(self.b))  
15.           
16. class C(A):  
17.     def __init__(self, c, **kw):  
18.         self.c=c  
19.         super(C, self).__init__(**kw)  
20.           
21.     def showC(self):  
22.         print("C.c={}".format(self.c))  
23.           
24. class D(B,C):  
25.     def __init__(self, a, b, c, d):  
26.         super(D, self).__init__(a=a, b=b, c=c)  
27.         self.d = d  
28.           
29.     def showD(self):  
30.         print("D.d={}".format(self.d))  
31.           
32. d = D(a='a', b='b', c='c', d='d')  
33. d.showA()  
34. d.showB()  
35. d.showC()  
36. d.showD()  

The execution result: 

A.a=a
B.b=b
C.c=c
D.d=d

Supplement 
* Tutorialspoint - Python 3 - Object Oriented