code: def iter_features(self, stanza=None):
          
          return itertools.chain(
              iter(self.STATIC_FEATURES),
              iter(self._features)
          )
docs: Return an iterator which yields the features of the node.
  
          :param stanza: The IQ request stanza
          :type stanza: :class:`~aioxmpp.IQ`
          :rtype: iterable of :class:`str`
          :return: :xep:`30` features of this node
  
          `stanza` is the :class:`aioxmpp.IQ` stanza of the request. This can be
          used to filter the list according to who is asking (not recommended).
  
          `stanza` may be :data:`None` if the features are queried without
          a specific request context. In that case, implementors should assume
          that the result is visible to everybody.
  
          .. note::
  
             Subclasses must allow :data:`None` for `stanza` and default it to
             :data:`None`.
  
          The features are returned as strings. The features demanded by
          :xep:`30` are always returned.