code: protected function getTreeByLanguageAndFieldAndSiteId($language, $field, $siteId)
      {
          $qa = $this->createAggregationQuery();
          $qa->match(
              array(
                  'siteId' => $siteId,
                  'language' => $language,
                  'status.publishedState' => true,
                  'deleted' => false,
                  $field => true
              )
          );
  
          return $this->hydrateAggregateQuery($qa);
      }
docs: @param string $language
  @param string $field
  @param string $siteId
  
  @return array
  @throws \Doctrine\ODM\MongoDB\MongoDBException