如何在Swift 3.0的UITextField菜单中隐藏粘贴选项？

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {

    @IBOutlet weak var textField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        textField.delegate = self
    }
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        let pasteboard = UIPasteboard.general
        if pasteboard.keyboardType == .paste {
            return false
        }
        return true
    }
}