How to use the @jupyterlab/outputarea.OutputAreaWidget.defaultContentFactory function in @jupyterlab/outputarea

it('should create an output area widget', () => {
          let factory = new CodeCellWidget.ContentFactory({ editorFactory });
          let model = new OutputAreaModel();
          let output = factory.createOutputArea({
            model,
            rendermime,
            contentFactory: OutputAreaWidget.defaultContentFactory
          });
          expect(output).to.be.an(OutputAreaWidget);
        });

it('should be a `contentFactory` instance', () => {
        expect(OutputAreaWidget.defaultContentFactory).to.be.an(OutputAreaWidget.ContentFactory);
      });

it('should take an optional contentFactory', () => {
        let contentFactory = Object.create(OutputAreaWidget.defaultContentFactory);
        let widget = new OutputAreaWidget({ rendermime, contentFactory, model });
        expect(widget.contentFactory).to.be(contentFactory);
      });