Python: replacing a function within a class of a module

Question

I\'m trying to replace a function defined within a class in order to modify its function (as in inner workings) without changing the actual code. I\'ve never done this befor

Answer 1

You can monkey patch this method as follows:

class TestMOD(object):

    def testFunc(self, variable):
        var = variable
        self.something = var + 12
        print(f'original {self.something}')


def alternativeFunc(self, variable):
    var = variable
    self.something = var + 1.2
    print(f'alternative {self.something}')


if __name__ == '__main__':

    test_original = TestMOD()
    test_original.testFunc(12)

    TestMOD.testFunc = alternativeFunc

    test_alternate = TestMOD()
    test_alternate.testFunc(12)

output:

original 24
alternative 13.2