code: def notifyOnDisconnect(self, callback):
          
          if self._disconnectCBs is None:
              self._disconnectCBs = []
          self._disconnectCBs.append(callback)
docs: Registers a callback that will be called when the DBus connection
          underlying the remote object is lost
  
          @type callback: Callable object accepting a L{RemoteDBusObject} and
                          L{twisted.python.failure.Failure}
          @param callback: Function that will be called when the connection to
                           the DBus session is lost. Arguments are the
                           L{RemoteDBusObject} instance and reason for the
                           disconnect (the same value passed to
                           L{twisted.internet.protocol.Protocol.connectionLost})