public static function isTraditional($str) {
    if (empty($str)) {
      throw new Exception('Argument str cannot be empty');
    }
    $ords = self::utf8ToUnicode($str);
    foreach ($ords as $val) {
      if (!empty($val) && array_key_exists($val, self::$trad2simple)) {
        return true;
      }
    }
    return false;
  }