How to use the @jupyterlab/notebook.NotebookWidgetFactory function in @jupyterlab/notebook

// Do nothing for sibling widgets for now.
    }
  };

  let docRegistry = new DocumentRegistry();
  let docManager = new DocumentManager({
    registry: docRegistry,
    manager,
    opener
  });
  let mFactory = new NotebookModelFactory({});
  let editorFactory = editorServices.factoryService.newInlineEditor.bind(
    editorServices.factoryService);
  let contentFactory = new NotebookPanel.ContentFactory({ editorFactory });

  let wFactory = new NotebookWidgetFactory({
    name: 'Notebook',
    modelName: 'notebook',
    fileExtensions: ['.ipynb'],
    defaultFor: ['.ipynb'],
    preferKernel: true,
    canStartKernel: true,
    rendermime, contentFactory,
    mimeTypeService: editorServices.mimeTypeService
  });
  docRegistry.addModelFactory(mFactory);
  docRegistry.addWidgetFactory(wFactory);

  let nbWidget = docManager.open(NOTEBOOK) as NotebookPanel;
  let palette = new CommandPalette({ commands });

  const editor = nbWidget.notebook.activeCell && nbWidget.notebook.activeCell.editor;

function activateNotebookHandler(app: JupyterLab, mainMenu: IMainMenu, palette: ICommandPalette, contentFactory: NotebookPanel.IContentFactory, editorServices: IEditorServices, restorer: ILayoutRestorer, rendermime: IRenderMimeRegistry, settingRegistry: ISettingRegistry, browserFactory: IFileBrowserFactory | null, launcher: ILauncher | null): INotebookTracker {
  const services = app.serviceManager;
  // An object for tracking the current notebook settings.
  let editorConfig = StaticNotebook.defaultEditorConfig;
  const factory = new NotebookWidgetFactory({
    name: FACTORY,
    fileTypes: ['notebook'],
    modelName: 'notebook',
    defaultFor: ['notebook'],
    preferKernel: true,
    canStartKernel: true,
    rendermime: rendermime,
    contentFactory,
    editorConfig,
    mimeTypeService: editorServices.mimeTypeService
  });
  const { commands, restored } = app;
  const tracker = new NotebookTracker({ namespace: 'notebook' });

  // Handle state restoration.
  restorer.restore(tracker, {

open: (widget: Widget) => {
      // Do nothing for sibling widgets for now.
    }
  };

  let docRegistry = new DocumentRegistry();
  let docManager = new DocumentManager({
    registry: docRegistry,
    manager,
    opener
  });
  let mFactory = new NotebookModelFactory({});
  let editorFactory = editorServices.factoryService.newInlineEditor;
  let contentFactory = new NotebookPanel.ContentFactory({ editorFactory });

  let wFactory = new NotebookWidgetFactory({
    name: 'Notebook',
    modelName: 'notebook',
    fileTypes: ['notebook'],
    defaultFor: ['notebook'],
    preferKernel: true,
    canStartKernel: true,
    rendermime,
    contentFactory,
    mimeTypeService: editorServices.mimeTypeService
  });
  docRegistry.addModelFactory(mFactory);
  docRegistry.addWidgetFactory(wFactory);

  let notebookPath = PageConfig.getOption('notebookPath');
  let nbWidget = docManager.open(notebookPath) as NotebookPanel;
  let palette = new CommandPalette({ commands });

open: (widget: Widget) => {
        // Do nothing for sibling widgets for now.
      }
    };

    let docRegistry = new DocumentRegistry();
    let docManager = new DocumentManager({
      registry: docRegistry,
      manager: this.props.serviceManager,
      opener
    });
    let mFactory = new NotebookModelFactory({});
    let editorFactory = editorServices.factoryService.newInlineEditor;
    let contentFactory = new NotebookPanel.ContentFactory({ editorFactory });

    let wFactory = new NotebookWidgetFactory({
      name: 'Notebook',
      modelName: 'notebook',
      fileTypes: ['notebook'],
      defaultFor: ['notebook'],
      preferKernel: true,
      canStartKernel: true,
      rendermime: this.props.rendermime,
      contentFactory,
      mimeTypeService: editorServices.mimeTypeService
    });
    docRegistry.addModelFactory(mFactory);
    docRegistry.addWidgetFactory(wFactory);

    this.nbWidget = docManager.open(this.props.notebookPath) as NotebookPanel;

    this.addCommands();

function activateNotebookHandler(app: JupyterLab, mainMenu: IMainMenu, palette: ICommandPalette, contentFactory: NotebookPanel.IContentFactory, editorServices: IEditorServices, restorer: ILayoutRestorer, browserFactory: IFileBrowserFactory | null, launcher: ILauncher | null): INotebookTracker {
  const services = app.serviceManager;
  const factory = new NotebookWidgetFactory({
    name: FACTORY,
    fileTypes: ['notebook'],
    modelName: 'notebook',
    defaultFor: ['notebook'],
    preferKernel: true,
    canStartKernel: true,
    rendermime: app.rendermime,
    contentFactory,
    mimeTypeService: editorServices.mimeTypeService
  });
  const { commands } = app;
  const tracker = new NotebookTracker({ namespace: 'notebook' });

  // Handle state restoration.
  restorer.restore(tracker, {
    command: 'docmanager:open',

open: (widget: Widget) => {
      // Do nothing for sibling widgets for now.
    }
  };

  let docRegistry = new DocumentRegistry();
  let docManager = new DocumentManager({
    registry: docRegistry,
    manager,
    opener
  });
  let mFactory = new NotebookModelFactory({});
  let editorFactory = editorServices.factoryService.newInlineEditor;
  let contentFactory = new NotebookPanel.ContentFactory({ editorFactory });

  let wFactory = new NotebookWidgetFactory({
    name: 'Notebook',
    modelName: 'notebook',
    fileTypes: ['notebook'],
    defaultFor: ['notebook'],
    preferKernel: true,
    canStartKernel: true,
    rendermime,
    contentFactory,
    mimeTypeService: editorServices.mimeTypeService
  });
  docRegistry.addModelFactory(mFactory);
  docRegistry.addWidgetFactory(wFactory);

  let notebookPath = PageConfig.getOption('notebookPath');
  let nbWidget = docManager.open(notebookPath) as NotebookPanel;
  let palette = new CommandPalette({ commands });

open: (widget: Widget) => {
      // Do nothing for sibling widgets for now.
    }
  };

  let docRegistry = new DocumentRegistry();
  let docManager = new DocumentManager({
    registry: docRegistry,
    manager,
    opener
  });
  let mFactory = new NotebookModelFactory({});
  let editorFactory = editorServices.factoryService.newInlineEditor;
  let contentFactory = new NotebookPanel.ContentFactory({ editorFactory });

  let wFactory = new NotebookWidgetFactory({
    name: 'Notebook',
    modelName: 'notebook',
    fileTypes: ['notebook'],
    defaultFor: ['notebook'],
    preferKernel: true,
    canStartKernel: true,
    rendermime,
    contentFactory,
    mimeTypeService: editorServices.mimeTypeService
  });
  docRegistry.addModelFactory(mFactory);
  docRegistry.addWidgetFactory(wFactory);

  let notebookPath = PageConfig.getOption('notebookPath');
  let nbWidget = docManager.open(notebookPath) as NotebookPanel;

function createFactory(
  toolbarFactory?: (widget: NotebookPanel) => DocumentRegistry.IToolbarItem[]
): NotebookWidgetFactory {
  return new NotebookWidgetFactory({
    name: 'notebook',
    fileTypes: ['notebook'],
    rendermime,
    toolbarFactory,
    contentFactory,
    mimeTypeService: NBTestUtils.mimeTypeService,
    editorConfig: NBTestUtils.defaultEditorConfig
  });
}