How to use the @projectstorm/react-diagrams.DefaultLabelFactory function in @projectstorm/react-diagrams

constructor() {
    this.diagramEngine = new SRD.DiagramEngine();

    this.diagramEngine.registerLinkFactory(new LinkWithContextFactory());
    this.diagramEngine.registerLabelFactory(new DefaultLabelFactory());

    this.diagramEngine.registerPortFactory(
      new SimplePortFactory("default", config => new DefaultPortModel())
    );
    this.diagramEngine.registerPortFactory(
      new SimplePortFactory("start", config => new CircleStartPortModel())
    );
    this.diagramEngine.registerPortFactory(
      new SimplePortFactory("end", config => new CircleEndPortModel())
    );
    this.diagramEngine.registerPortFactory(
      new SimplePortFactory("fork", config => new ForkNodePortModel())
    );
    this.diagramEngine.registerPortFactory(
      new SimplePortFactory("join", config => new JoinNodePortModel())
    );