code: def registration_success(self, stanza):
          
          _unused = stanza
          self.lock.acquire()
          try:
              self.state_change("registered", self.registration_form)
              if ('FORM_TYPE' in self.registration_form
                      and self.registration_form['FORM_TYPE'].value == 'jabber:iq:register'):
                  if 'username' in self.registration_form:
                      self.my_jid = JID(self.registration_form['username'].value,
                              self.my_jid.domain, self.my_jid.resource)
                  if 'password' in self.registration_form:
                      self.password = self.registration_form['password'].value
              self.registration_callback = None
              self._post_connect()
          finally:
              self.lock.release()
docs: Handle registration success.
  
          [client only]
  
          Clean up registration stuff, change state to "registered" and initialize
          authentication.
  
          :Parameters:
              - `stanza`: the stanza received.
          :Types:
              - `stanza`: `pyxmpp.iq.Iq`