如何在swift 3中动态增加滚动窗口的高度？

import UIKit

class ViewController: UIViewController {
    @IBOutlet weak var scrollView: UIScrollView!
    @IBOutlet weak var contentView: UIView!
    @IBOutlet weak var addButton: UIButton!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 设置滚动窗口的内容大小
        scrollView.contentSize = contentView.frame.size
    }
    
    @IBAction func addButtonTapped(_ sender: UIButton) {
        // 获取滚动窗口的当前高度
        let currentHeight = scrollView.frame.height
        
        // 计算要增加的高度值
        let additionalHeight: CGFloat = 100
        
        // 创建新的CGRect对象，增加高度
        let newFrame = CGRect(x: scrollView.frame.origin.x, y: scrollView.frame.origin.y, width: scrollView.frame.width, height: currentHeight + additionalHeight)
        
        // 更新滚动窗口的高度
        scrollView.frame = newFrame
        
        // 更新滚动窗口的内容大小
        scrollView.contentSize = contentView.frame.size
    }
}