How to use the @jupyterlab/testutils.NBTestUtils.createBaseCellFactory function in @jupyterlab/testutils

it('should accept a custom contentFactory', () => {
        const contentFactory = NBTestUtils.createBaseCellFactory();
        const widget = new Cell({ model, contentFactory }).initializeState();
        expect(widget).toBeInstanceOf(Cell);
      });

describe('MarkdownCell', () => {
    const contentFactory = NBTestUtils.createBaseCellFactory();
    const model = new MarkdownCellModel({});

    describe('#constructor()', () => {
      it('should create a markdown cell widget', () => {
        const widget = new MarkdownCell({ model, rendermime, contentFactory });
        widget.initializeState();
        expect(widget).toBeInstanceOf(MarkdownCell);
      });

      it('should accept a custom contentFactory', () => {
        const widget = new MarkdownCell({ model, rendermime, contentFactory });
        widget.initializeState();
        expect(widget).toBeInstanceOf(MarkdownCell);
      });

      it('should set the default mimetype to text/x-ipythongfm', () => {

constructor() {
    super({
      model: new CellModel({}),
      contentFactory: NBTestUtils.createBaseCellFactory()
    });
  }

constructor() {
    super({
      model: new CellModel({}),
      contentFactory: NBTestUtils.createBaseCellFactory()
    });
  }