我可以限制UITextField的字符集吗？

class CustomTextField: UITextField {
    override func willMove(toSuperview newSuperview: UIView?) {
        super.willMove(toSuperview: newSuperview)
        addTarget(self, action: #selector(editingChanged), for: .editingChanged)
    }

    @objc func editingChanged(textField: UITextField) {
        let validChars = "0123456789"
        let validCharSet = CharacterSet(charactersIn: validChars)
        let filteredString = textField.text?.components(separatedBy: validCharSet.inverted).joined()
        if textField.text != filteredString {
            textField.text = filteredString
        }
    }
}