code: def get_private_xml(self, query_xso):
          
          iq = aioxmpp.IQ(
              type_=aioxmpp.IQType.GET,
              payload=private_xml_xso.Query(query_xso)
          )
          return (yield from self.client.send(iq))
docs: Get the private XML data for the element `query_xso` from the
          server.
  
          :param query_xso: the object to retrieve.
          :returns: the stored private XML data.
  
          `query_xso` *must* serialize to an empty XML node of the
          wanted namespace and type and *must* be registered as private
          XML :class:`~private_xml_xso.Query` payload.