code: def to_xml(self):
          
          element = etree.Element(self._tag_name)
          struct_to_xml(element, [
              {"author": self.handle},
              {"recipient": self.target_handle},
              {"following": "true" if self.following else "false"},
              {"sharing": "true" if self.following else "false"},
          ])
          return element
docs: Convert to XML message.