如何以编程方式将光标移动到下一个UITextField？

class ViewController: UIViewController {

    @IBOutlet weak var textField1: UITextField!
    @IBOutlet weak var textField2: UITextField!
    @IBOutlet weak var textField3: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()

        let tapGesture = UITapGestureRecognizer(target: self, action: #selector(handleTap))
        view.addGestureRecognizer(tapGesture)
    }

    @objc func handleTap(sender: UITapGestureRecognizer) {
        guard let currentTextField = view.currentFirstResponder as? UITextField else {
            return
        }

        if currentTextField == textField1 {
            textField2.becomeFirstResponder()
        } else if currentTextField == textField2 {
            textField3.becomeFirstResponder()
        } else if currentTextField == textField3 {
            textField1.becomeFirstResponder()
        }
    }
}

extension UIView {
    var currentFirstResponder: UIResponder? {
        if self.isFirstResponder {
            return self
        }

        for subView in self.subviews {
            if let responder = subView.currentFirstResponder {
                return responder
            }
        }

        return nil
    }
}