static function fromSuccessResponse($success_response)
    {
        $obj = new Auth_OpenID_PAPE_Response();

        // PAPE requires that the args be signed.
        $args = $success_response->getSignedNS(Auth_OpenID_PAPE_NS_URI);

        if ($args === null || $args === array()) {
            return null;
        }

        $result = $obj->parseExtensionArgs($args);

        if ($result === false) {
            return null;
        } else {
            return $obj;
        }
    }