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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 _unpublish(self):
 """ Process an unpublish action on the related object, returns a boolean if a change is made. Only objects with a current active version will be updated. """

        obj = self.content_object
        actioned = False

        # Only update if needed
        if obj.current_version is not None:
            obj.current_version = None
            obj.save(update_fields=['current_version'])
            actioned = True

        return actioned