docs: def update_xml_element(self):
          """
          Updates the xml element contents to matches the instance contents.
  
          :returns: Updated XML element.
          :rtype: lxml.etree._Element
          """
  
          if not hasattr(self, 'xml_element'):
              self.xml_element = etree.Element(self.name, nsmap=NSMAP)
  
          if hasattr(self, 'idref'):
              self.xml_element.set('idref', self.idref)
  
          return self.xml_element