Method Resolution Order

MRO stands for Method Resolution Order. It says that whenever there is multiple inheritance of 2 or more parent classes by one base class, unlike c++, in case of an overloading, the methods and constructors are called in order of left to right .

class A:
    #Python variant of function object of c++
    def __call__(self, x):
        return "Value passed from class-A = "+str(x)
    def __init__(self):
        print("Constructor of class A is called")

class B:
    def __call__(self, x):
        return "Value passed from class-B = "+str(x)
    def __init__(self):
        print("Constructor of class B is called")

Driver code-1

if __name__=="__main__":
    class C(A,B):
        pass
    a = C()
    print(a("Hello"))

Constructor of class A is called
Value passed from class-A = Hello

Driver code-2

if __name__=="__main__":
    class D(B,A):
        pass
    b = D()
    print(b("World"))

Constructor of class B is called
Value passed from class-B = World

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