public static function payMethods($lang = null)
    {

        try {
            $authType = self::getAuth();
        } catch (OpenPayU_Exception $e) {
            throw new OpenPayU_Exception($e->getMessage(), $e->getCode());
        }

        if (!$authType instanceof AuthType_Oauth) {
            throw new OpenPayU_Exception_Configuration('Retrieve works only with OAuth');
        }

        $pathUrl = OpenPayU_Configuration::getServiceUrl() . self::PAYMETHODS_SERVICE;
        if ($lang !== null) {
            $pathUrl .= '?lang=' . $lang;
        }

        $response = self::verifyResponse(OpenPayU_Http::doGet($pathUrl, $authType));

        return $response;
    }