public function checkFolderIsEmptyOrNot(string $folderName):bool
    {
        $files = array ();
        if ($handle = opendir($folderName)) {
            while (false !== ($file = readdir($handle))) {
                if ($file != "." && $file != "..") {
                    $files [] = $file;
                }
            }
            closedir($handle);
        }
        return ((count($files) === 0) ?  true : false);
    }