public void handleAddRequest(T model)
        {
            ModelMessageResult <T> response = request_handler.handleAdded(model);

            if (response.Error == null)
            {
                addViewVM(response.NewModel);
            }
            setErrorAndMessage(response);
        }
        private void handleUpdateRequest(T model, IUpdater <T> updater)
        {
            ModelMessageResult <T> response = request_handler.handleEdited(model, updater);

            if (response.Error == null)
            {
                replaceWithViewVm(model, response.NewModel);
            }
            setErrorAndMessage(response);
        }