/**
  * Populates a CategoryGroupModel with attributes from a CategoryGroupRecord.
  *
  * @param CategoryGroupRecord|null
  *
  * @return CategoryGroupModel|null
  */
 private function _populateCategoryGroupFromRecord($groupRecord)
 {
     if (!$groupRecord) {
         return null;
     }
     $group = CategoryGroupModel::populateModel($groupRecord);
     if ($groupRecord->structure) {
         $group->maxLevels = $groupRecord->structure->maxLevels;
     }
     return $group;
 }