code: def disconnect_user(self):
          
          if self.session_logged_in():
              self._logger.info("User %s disconnected - %s - %s - %s", self.session_username(), self.session_realname(), self.session_email(), web.ctx.ip)
          self._destroy_session()
docs: Disconnects the user currently logged-in
          :param ip_addr: the ip address of the client, that will be logged