changing the class of a python object (casting)

Question

On this python doc page it says:

Like its identity, an object’s type is also unchangeable.

And I try this script,

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Answer 1

I was asked this question by a colleague today. He had a parent class that wanted to promote itself automatically to be one of its children based on an input at init time. The following script worked as a proof of concept:

class ClassB(object):

    def __init__(self):
        self.__class__ = ClassA

    def blah2(self,t):
        print('I give you',t)
        return 'You are welcome'

class ClassA(ClassB):

   def blah(self, t):
       print('you gave me',t)
       return 'Thankyou'



a = ClassB()
print(type(a))
print(a.blah('sausage'))
print(a.blah2('cabbage'))

The result shows:

you gave me sausage
Thankyou
I give you cabbage
You are welcome

Which shows that both the parent and child functions are now available to A.