Swift错误：Braced Block of Statements是一个未使用的闭包

Here's my Code (2 errors):

这是我的代码（2个错误）：

override func viewDidLoad() {
    super.viewDidLoad()


    //ERROR HERE - "Expected type after as"
    let skView = view as! SKView
    skView.multipleTouchEnabled = false

    //Create and configure the scene
    scene = GameScene(size: skView.bounds.size)
    scene.scaleMode = .AspectFill

    scene.tick = didTick

    swiftris = Swiftris()
    swiftris.beginGame()

    //Present the scene
    skView.presentScene(scene)

    //ERROR HERE - Braced block of statements is an unused closure
        scene.addPreviewShapeToScene(swiftris.nextShape!){
        self.swiftris.nextShape?.moveTo(StartingColumn, row: StartingRow)
        self.scene.movePreviewShape(self.swiftris.nextShape!){
            let nextShapes = self.swiftris.newShape()
            self.scene.startTicking()
            self.scene.addPreviewShapeToScene(nextShapes.nextShape!) {}
        }
    }
}
ov