code: def fetch(self):
          
          from ..iq import Iq
          jid,node = self.address
          iq = Iq(to_jid = jid, stanza_type = "get")
          disco = self.disco_class(node)
          iq.add_content(disco.xmlnode)
          self.stream.set_response_handlers(iq,self.__response, self.__error,
                  self.__timeout)
          self.stream.send(iq)
docs: Initialize the Service Discovery process.