code: private function _getUpdated (Element $type, $id)
  	{
  		/** @var EntryQuery|CategoryQuery $criteria */
  		$criteria = $type::find();
  
  		$this->_setCriteriaIdByType($criteria, $type, $id);
  
  		$criteria->limit = 1;
  
  		$element = $criteria->one();
  		return $element ? $element->dateUpdated->format('c') : '';
  	}
docs: Get's the latest updated element date for the given element type and
  group / section ID
  
  @param Element $type - The Element Type
  @param int     $id - The section or group ID
  
  @return \DateTime|string