Call overridden method of parent class with child class object in python

Question

I have came around this question during an interview:

class Parent(object):
    def A(self):
        print \"in A\"
class Child(Parent):
    def A(self):
                


        

Answer 1

As you see, methods of objects always have the self parameter.

You can call objects methods as

C.A()

or equivalently, by explicitly passing the self parameter, as:

Child.A(C)

In the second way, you can call also the method of the parent class using the C instance:

Parent.A(C)

If you are looking for a general method to solve this (i.e. without knowing the name of the parent class), you can use super() and type():

super(type(C)).A(C)

However, super() has a nice additional argument to specify an object instance, so you could write also:

super(type(C), C).A()

Answer 2

You can use super() builtin.

>>> super(Child, C).A()
in A

It is usually used to call super class implementation inside subclasses, but it is also allowed outside. Docs state:

Also note that super() is not limited to use inside methods. The two argument form specifies the arguments exactly and makes the appropriate references.

Answer 3

Call the method on the class explicitly.

Parent.A(C)

Answer 4

Use a super call passing the type of child class and the desired instance object which is just C:

super(type(C), C).A() # of the form super(class, obj) where class == Child and obj == C

Answer 5

Having instance C we could get its base class and call its A():
C.__class__.__base__().A()