public static function check_name(): bool
  {

    $args = \func_get_args();
    // Each argument must be a string starting with a letter, and having only one character made of letters, numbers and underscores
    foreach ( $args as $a ){
      $a = self::cast($a);
      $t = preg_match('#[A-z0-9_]+#',$a,$m);
      if ( $t !== 1 || $m[0] !== $a ){
        return false;
      }
    }

    return true;
  }