code: def complete_xml_element(self, xmlnode, _unused):
          
          for _unused1, value in self.content.items():
              if value is None:
                  continue
              if type(value) is list:
                  for v in value:
                      v.as_xml(xmlnode)
              else:
                  value.as_xml(xmlnode)
docs: Complete the XML node with `self` content.
  
          Should be overriden in classes derived from `StanzaPayloadObject`.
  
          :Parameters:
              - `xmlnode`: XML node with the element being built. It has already
                right name and namespace, but no attributes or content.
              - `_unused`: document to which the element belongs.
          :Types:
              - `xmlnode`: `libxml2.xmlNode`
              - `_unused`: `libxml2.xmlDoc`