public function processModification($siteGroupId = null)
    {
        if ($this->connector->getURL() === null) {
            return 'Cannot find site URL from configuration.';
        }
        $url = $this->connector->getURL().self::VERSION.'/process';
        $params = [
          'sitegroup_id' => $siteGroupId,
        ];
        $response = $this->connector->connecting($url, $params, 'POST');
        if (isset($response->sitegroups)) {
            return $response->message;
        }

        return $response;
    }