问为什么当我使用CASpringAnimation时，我的图像没有动画？

EN

lazy var profileImageView: UIImageView = {
    let imageView = UIImageView()
    imageView.image = UIImage(named: "made")
    imageView.translatesAutoresizingMaskIntoConstraints = false
    imageView.contentMode = .scaleAspectFill
    imageView.addGestureRecognizer(UITapGestureRecognizer(target: self, action: #selector(taptap)))
    imageView.isUserInteractionEnabled = true
    return imageView
}()

@objc func taptap() {
    let pulse = CASpringAnimation(keyPath: "transform.scale")
    pulse.duration = 0.6
    pulse.fromValue = 0.95
    pulse.toValue = 1.0
    pulse.autoreverses = true
    pulse.repeatCount = 2
    pulse.initialVelocity = 0.5
    pulse.damping = 1.0
    layer.add(pulse, forKey: nil)
}