code: public function collectRules($filterSettings)
      {
          $information = $this->database
              ->createQueryBuilder()
              ->select('*')
              ->from('tl_metamodel_filtersetting')
              ->where('fid=:fid')
              ->andWhere('pid=0')
              ->andWhere('enabled=1')
              ->orderBy('sorting', 'ASC')
              ->setParameter('fid', $filterSettings->get('id'))
              ->execute();
  
          foreach ($information->fetchAll(\PDO::FETCH_ASSOC) as $item) {
              $newSetting = $this->createSetting($item, $filterSettings);
              if ($newSetting) {
                  $filterSettings->addSetting($newSetting);
              }
          }
      }
docs: Collect the rules for a filter setting.
  
  @param Collection $filterSettings The filter settings instance.
  
  @return void