Swift -如何限制几个特定的文本字段只允许插入int？

import UIKit

class ViewController: UIViewController, UITextFieldDelegate {
    
    @IBOutlet weak var numberTextField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        numberTextField.delegate = self
    }
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        // 获取文本字段当前的文本内容
        guard let text = textField.text else {
            return true
        }
        
        // 将当前的文本内容与即将插入的字符串拼接
        let newText = (text as NSString).replacingCharacters(in: range, with: string)
        
        // 尝试将拼接后的字符串转换为整数
        if let _ = Int(newText) {
            return true
        } else {
            return false
        }
    }
}