public function getPaymentMethodGroups()
    {
        $response = $this->sendRequest(
            $this->serviceBaseUrl . 'GetPaymentMethods',
            ['MerchantLogin' => $this->auth->getMerchantLogin(), 'Language' => $this->culture],
            $this->requestMethod
        );

        $sxe = simplexml_load_string($response);
        $this->parseError($sxe);

        if (!$sxe->Methods->Method) {
            return [];
        }
        $methods = [];
        foreach ($sxe->Methods->Method as $method) {
            $methods[(string)$method->attributes()->Code] = (string)$method->attributes()->Description;
        }
        return $methods;
    }