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

constructor() {
		super({ name: 'starting-state' });
		this.childStates = [new SelectingState()];
		this.dragCanvas = new DragCanvasState();
		this.createLink = new CreateLinkState();
		this.dragItems = new DragDiagramItemsState();

		// determine what was clicked on
		this.registerAction(
			new Action({
				type: InputType.MOUSE_DOWN,
				fire: (event: ActionEvent) => {
					const element = this.engine.getActionEventBus().getModelForEvent(event);

					// the canvas was clicked on, transition to the dragging canvas state
					if (!element) {
						this.transitionWithEvent(this.dragCanvas, event);
					}
					// initiate dragging a new link
					else if (element instanceof PortModel) {
						return;
					}