public static function safe(string $string) : string
  {
    $split = str_split($string);

    foreach($split as $k => $char) {
      if (str_contains('~!@#$%^&*()_-=+<>/\?;:{}[]|,.', $char)) {
        unset($split[$k]);
      }
    }

    return implode('', $split);
  }