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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 activate(self, user):
 """ Updates the `invitee` value and saves the instance Provided as a way of extending the behavior. Args: user: the newly created user Returns: the linking organization user """

        org_user = self.organization.add_user(user, **self.activation_kwargs())
        self.invitee = user
        self.save()
        return org_user