public function getOption($optionName = null)
    {
        if ($this->multiSite) {
            $options = get_site_option($this->settingsName);
        } else {
            $options = get_option($this->settingsName);
        }
        if (!$optionName)
            return $options;

        if (is_array($options) && isset($options[$optionName]))
            return $options[$optionName];
        foreach ($this->settings as $setting) {
            if ($setting['name'] == $optionName) {
                if (!empty($setting['default']))
                    return $setting['default'];
                break;
            }
        }
        return null;
    }