在swift 3中如何在UItextField中使用波斯数字？

class ViewController: UIViewController, UITextFieldDelegate {
    @IBOutlet weak var textField: UITextField!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        textField.delegate = self
    }
    
    // 其他代码...
}

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    let persianDigits = ["۰", "۱", "۲", "۳", "۴", "۵", "۶", "۷", "۸", "۹"]
    
    var updatedString = ""
    for character in string {
        if let digit = Int(String(character)) {
            updatedString += persianDigits[digit]
        } else {
            updatedString += String(character)
        }
    }
    
    textField.text?.replaceSubrange(range, with: updatedString)
    
    return false
}