code: def payload_element_name(element_name):
      
      def decorator(klass):
          """The payload_element_name decorator."""
          # pylint: disable-msg=W0212,W0404
          from .stanzapayload import STANZA_PAYLOAD_CLASSES
          from .stanzapayload import STANZA_PAYLOAD_ELEMENTS
          if hasattr(klass, "_pyxmpp_payload_element_name"):
              klass._pyxmpp_payload_element_name.append(element_name)
          else:
              klass._pyxmpp_payload_element_name = [element_name]
          if element_name in STANZA_PAYLOAD_CLASSES:
              logger = logging.getLogger('pyxmpp.payload_element_name')
              logger.warning("Overriding payload class for {0!r}".format(
                                                                  element_name))
          STANZA_PAYLOAD_CLASSES[element_name] = klass
          STANZA_PAYLOAD_ELEMENTS[klass].append(element_name)
          return klass
      return decorator
docs: Class decorator generator for decorationg
      `StanzaPayload` subclasses.
  
      :Parameters:
          - `element_name`: XML element qname handled by the class
      :Types:
          - `element_name`: `unicode`