public function customize(array $arr): array
  {
    $res = [];
    if ( isset($arr[0]) ){
      foreach ( $arr as $a ){
        if ( isset($a['id']) && $this->has($a['id']) ){
          $res[] = $a;
        }
      }
    }
    else if ( isset($arr['items']) ){
      $res = $arr;
      unset($res['items']);
      foreach ( $arr['items'] as $a ){
        if ( isset($a['id']) && $this->has($a['id']) ){
          if ( !isset($res['items']) ){
            $res['items'] = [];
          }
          $res['items'][] = $a;
        }
      }
    }
    return $res;
  }