def METHOD_NAME(self):
    """ Test that protecting an already protected document
    does not raise an error.
    """
    request_body = {
        'document_id': self.waypoint2.document_id
    }
    headers = self.add_authorization_header(username='moderator')
    self.app_post_json(
        self._prefix, request_body, status=200, headers=headers)
    self.assertTrue(self.is_protected(self.waypoint2.document_id))