animationDidStop方法的多个CAAnimations？

let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
rotationAnimation.toValue = CGFloat.pi * 2.0
rotationAnimation.duration = 2.0

let scaleAnimation = CABasicAnimation(keyPath: "transform.scale")
scaleAnimation.toValue = 1.5
scaleAnimation.duration = 2.0

let layer = view.layer
layer.add(rotationAnimation, forKey: "rotationAnimation")
layer.add(scaleAnimation, forKey: "scaleAnimation")

func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
    if let key = anim.value(forKey: "key") as? String {
        print("Animation \(key) stopped")
    }
}

layer.delegate = self

rotationAnimation.delegate = self
scaleAnimation.delegate = self