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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_callable_attr(self, attr_name):
 """Used to double methods added to an object after creation :param str attr_name: the name of the original attribute to return :return: Attribute or None. :rtype: func """


        if not hasattr(self.doubled_obj, attr_name):
            return None

        func = getattr(self.doubled_obj, attr_name)
        if not is_callable(func):
            return None

        attr = Attribute(
            func,
            'attribute',
            self.doubled_obj if self.is_class_or_module() else self.doubled_obj_type,
        )
        self.attrs[attr_name] = attr
        return attr