private function mergeSettings($settingsa, &$settingsb)
    {
        foreach ($settingsb as $key => &$value) {
            if (isset($settingsa[$key])) {
                if (is_array($value)) {
                    $this->mergeSettings($settingsa[$key], $value);
                } else {
                    $value = $settingsa[$key];
                }
            }
        }
    }