code: protected function filterSearch(PaginateFinderConfiguration $configuration, Stage $qa)
      {
          $label = $configuration->getSearchIndex('label');
          $language = $configuration->getSearchIndex('language');
  
          if (null !== $label && '' !== $label && null !== $language && '' !== $language) {
              $qa->match(array('labels.' . $language => new \MongoRegex('/.*'.$label.'.*/i')));
          }
  
          return $qa;
      }
docs: @param PaginateFinderConfiguration $configuration
  @param Stage                       $qa
  
  @return array