public static function bytesToHuman($bytes, $decimals = 2)
    {
        $bytes = max($bytes, 0);
        $pow = floor(($bytes ? log($bytes) : 0) / log(self::KILOBYTE));
        $pow = min($pow, count(self::$byte_units) - 1);
        $bytes /= pow(self::KILOBYTE, $pow);
        
        return self::numberFormat($bytes, $decimals) . self::$byte_units[$pow];
    }