public static function getParam($key, $defaultValue = null, $module = null)
    {
        if(null !== $module) {
            return self::getParam(strtolower($module) . '.' . $key, self::getParam($key, $defaultValue));
        }
        $param = self::getInstance()->get($key);
        return (null !== $param) ? $param : $defaultValue;
    }