public static function needs($sNeedle, $sCallback = null, $aArgs = null)
    {
        if (!is_null(static::get($sNeedle))) {
            return true;
        } elseif (!is_null($sCallback)) {
            if (is_array($aArgs)) {
                return call_user_func_array($sCallback, $aArgs);
            }

            return call_user_func($sCallback);
        }

        return false;
    }