How to use the @jupyter-widgets/base.JUPYTER_WIDGETS_VERSION function in @jupyter-widgets/base

.catch((reason: Error) => {
          console.error(`Failed to set ${plugin.id}: ${reason.message}`);
        });
    },
    isToggled: () => SETTINGS.saveState
  });

  if (menu) {
    menu.settingsMenu.addGroup([
      {command: '@jupyter-widgets/jupyterlab-manager:saveWidgetState'}
    ]);
  }

  WIDGET_REGISTRY.push({
    name: '@jupyter-widgets/base',
    version: base.JUPYTER_WIDGETS_VERSION,
    exports: {
      WidgetModel: base.WidgetModel,
      WidgetView: base.WidgetView,
      DOMWidgetView: base.DOMWidgetView,
      DOMWidgetModel: base.DOMWidgetModel,
      LayoutModel: base.LayoutModel,
      LayoutView: base.LayoutView,
      StyleModel: base.StyleModel,
      StyleView: base.StyleView
    }
  });

  WIDGET_REGISTRY.push({
    name: '@jupyter-widgets/controls',
    version: JUPYTER_CONTROLS_VERSION,
    exports: () => {

_registerWidgets() {
        this.register({
            name: '@jupyter-widgets/base',
            version: base.JUPYTER_WIDGETS_VERSION,
            exports: base
        });
        this.register({
            name: '@jupyter-widgets/controls',
            version: controls.JUPYTER_CONTROLS_VERSION,
            exports: controls
        });
        this.register({
            name: '@jupyter-widgets/output',
            version: output.OUTPUT_WIDGET_VERSION,
            exports: output
        });
    }