public CarAndDriverPackage EditDriver(IModalDialogService modalDialogService, IServiceFactory serviceFactory,
     CarAndDriverPackage selectedCarAndDriver)
 {
     var viewModel = new UpdateDriverViewModel(modalDialogService, serviceFactory);
       viewModel.CarAndDriver = selectedCarAndDriver;
       viewModel.DialogMode = DialogMode.Update;
       ModalDialogHelper<UpdateDriver>.ShowDialog(viewModel);
       return viewModel.CarAndDriver;
 }
 public CarAndDriverPackage CreateDriver(IModalDialogService modalDialogService, IServiceFactory serviceFactory)
 {
     var viewModel = new UpdateDriverViewModel(modalDialogService, serviceFactory);
       viewModel.CarAndDriver = new CarAndDriverPackage();
       viewModel.DialogMode = DialogMode.Create;
       ModalDialogHelper<UpdateDriver>.ShowDialog(viewModel);
       if (!viewModel.IsCanceled)
       {
     return viewModel.CarAndDriver;
       }
       return null;
 }