如何在用户键入时将uitextfield中的光标移动到第二个字符

let textField = UITextField(frame: CGRect(x: 0, y: 0, width: 200, height: 40))
self.view.addSubview(textField)

class ViewController: UIViewController, UITextFieldDelegate {
    override func viewDidLoad() {
        super.viewDidLoad()
        textField.delegate = self
    }
    
    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        // 在这里处理文本变化事件
        // 如果当前输入的是第一个字符，则将光标移动到第二个字符
        if range.location == 0 && range.length == 0 {
            let newPosition = textField.position(from: textField.beginningOfDocument, offset: 1)
            textField.selectedTextRange = textField.textRange(from: newPosition!, to: newPosition!)
        }
        return true
    }
}