public static function convert_uids($st){
    if ( \is_array($st) || \is_object($st) ){
      foreach ( $st as &$s ){
        $s = self::convert_uids($s);
      }
    }
    else if ( \bbn\str::is_uid($st) ){
      $st = bin2hex($st);
    }
    return $st;
  }