code: private function buildWhere(QueryBuilder $queryBuilder, $mixIds, $mixLangCode = '')
      {
          $queryBuilder
              ->andWhere('att_id = :att_id')
              ->setParameter('att_id', $this->get('id'));
  
          if (!empty($mixIds)) {
              if (is_array($mixIds)) {
                  $queryBuilder
                      ->andWhere('item_id IN (:item_ids)')
                      ->setParameter('item_ids', $mixIds, Connection::PARAM_STR_ARRAY);
              } else {
                  $queryBuilder
                      ->andWhere('item_id = :item_id')
                      ->setParameter('item_id', $mixIds);
              }
          }
  
          if (!empty($mixLangCode)) {
              if (is_array($mixLangCode)) {
                  $queryBuilder
                      ->andWhere('langcode IN (:langcode)')
                      ->setParameter('langcode', $mixLangCode, Connection::PARAM_STR_ARRAY);
              } else {
                  $queryBuilder
                      ->andWhere('langcode = :langcode')
                      ->setParameter('langcode', $mixLangCode);
              }
          }
      }
docs: Build a where clause for the given id(s) and language code.
  
  @param QueryBuilder         $queryBuilder The query builder for the query  being build.
  
  @param string[]|string|null $mixIds       One, none or many ids to use.
  
  @param string|string[]      $mixLangCode  The language code/s to use, optional.
  
  @return void