how to use dragbones getbone??

[a6965921]

how to use dragbones getbone??
` const app = new PIXI.Application({ antialias: true });
document.body.appendChild(app.view);

app.stop();

// load spine data
PIXI.Loader.shared
    .add('skeleton', '/moban/dragonbones/Dragon_ske.json')
    .add('texture_json', '/moban/dragonbones/Dragon_tex.json')
    .add('texture_png', '/moban/dragonbones/Dragon_tex.png')
    .load(onAssetsLoaded);

function onAssetsLoaded(loader, res) {
    const factory = dragonBones.PixiFactory.factory;

    factory.parseDragonBonesData(res.skeleton.data);
    factory.parseTextureAtlasData(res.texture_json.data, res.texture_png.texture);
    var armature = factory.buildArmature("Dragon");
    // var armatureDisplay = armature.getDisplay();
    var armatureDisplay = factory.buildArmatureDisplay('Dragon', 'Dragon');
    // armatureDisplay.animation.play('walk');
    armatureDisplay.x = 400.0;
    armatureDisplay.y = 400.0;
    armatureDisplay.scale.x = 0.6;
    armatureDisplay.scale.y = 0.6;
     //调整动画速度
    // armatureDisplay.animation.timeScale = 0.1;

    //控制骨骼旋转
    var head =armature.getBone("head");
    head.offset.rotation = 0.6;
    head.invalidUpdate();
    app.stage.addChild(armatureDisplay);
    // setTimeout(function() {
    //     armatureDisplay.animation.play('stand');
    //     setTimeout(function() {
    //         armatureDisplay.animation.play('walk');
    //     }, 2000)
    // }, 2000)

    app.start();
}`

this is no effect