'Make an extended request of the server.
The method returns a Deferred that is called back with
the result of the extended request.
@type request: L{bytes}
@param request: the name of the extended request to make.
@type data: L{bytes}
@param data: any other data that goes along with the request.'

def extendedRequest(self, request, data):

    return self._sendRequest(FXP_EXTENDED, (NS(request) + data))
