如何在使用Swift呈现新的Viewcontroller后取消以前的Viewcontroller？

navigationController?.popViewController(animated: true)

dismiss(animated: true, completion: nil)

protocol ViewControllerDelegate: AnyObject {
    func viewControllerDidCancel(_ viewController: UIViewController)
}

class NewViewController: UIViewController {
    weak var delegate: ViewControllerDelegate?

    // 取消按钮点击事件
    @IBAction func cancelButtonTapped(_ sender: UIButton) {
        delegate?.viewControllerDidCancel(self)
    }
}

class CurrentViewController: UIViewController, ViewControllerDelegate {
    // 呈现新的Viewcontroller
    func presentNewViewController() {
        let newViewController = NewViewController()
        newViewController.delegate = self
        present(newViewController, animated: true, completion: nil)
    }

    // 实现代理方法
    func viewControllerDidCancel(_ viewController: UIViewController) {
        dismiss(animated: true, completion: nil)
    }
}

@IBAction func cancelButtonTapped(_ sender: UIButton) {
    NotificationCenter.default.post(name: NSNotification.Name("CancelNotification"), object: nil)
}

class CurrentViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        NotificationCenter.default.addObserver(self, selector: #selector(cancelViewController), name: NSNotification.Name("CancelNotification"), object: nil)
    }

    deinit {
        NotificationCenter.default.removeObserver(self)
    }

    @objc func cancelViewController() {
        dismiss(animated: true, completion: nil)
    }
}