code: public function saveProps($selected = [])
      {
          $propertyValues = $this->constructPropertyValuesForSave($selected);
          if (empty($propertyValues)) {
              return false;
          }
  
          $bxMethod = empty($selected) ? 'setPropertyValues' : 'setPropertyValuesEx';
          static::$bxObject->$bxMethod(
              $this->id,
              static::iblockId(),
              $propertyValues
          );
  
          return true;
      }
docs: Save props to database.
  If selected is not empty then only props from it are saved.
  
  @param array $selected
  
  @return bool