I want to use a picker for two different text boxes

In one if it works for me but in the other when it is time to accept or cancel, it sends me an error.

func createDataPicker(_ textField : UITextField)
    {
        self.picker = UIDatePicker(frame:CGRect(x: 0, y: 0, width: self.view.frame.size.width, height: 216))
        self.picker.backgroundColor = UIColor.white
        self.picker.datePickerMode = UIDatePickerMode.date
        let loc = Locale(identifier: "es")
        self.picker.locale = loc

        let toolBar = UIToolbar()
        toolBar.barStyle = .default
        toolBar.isTranslucent = true
        toolBar.tintColor = UIColor(red: 92/255, green: 216/255, blue: 255/255, alpha: 1)
        toolBar.sizeToFit()

        let doneButton = UIBarButtonItem(title: "Aceptar", style: .plain, target: self, action: #selector(ViewController.doneClick(textField:)))
        let spaceButton = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
        let cancelButton = UIBarButtonItem(title: "Cancelar", style: .plain, target: self, action: #selector(ViewController.cancelClick(textField:)))
        toolBar.setItems([cancelButton, spaceButton, doneButton], animated: false)
        toolBar.isUserInteractionEnabled = true

        textField.inputAccessoryView = toolBar
        textField.inputView = self.picker

        //dateRegistro.inputAccessoryView = toolBar
        //dateRegistro.inputView = self.picker
    }


    //Función de la fecha
    @objc func doneClick(textField: UITextField) {
        let dateFormatter1 = DateFormatter()
        dateFormatter1.dateFormat = "dd/MM/yyyy"

        //textField.text = dateFormatter1.string(from: picker.date)
        //textField.resignFirstResponder()

        dateField.text = dateFormatter1.string(from: picker.date)
        dateField.resignFirstResponder()

        //dateRegistro.text = dateFormatter1.string(from: picker.date)
        //dateRegistro.resignFirstResponder()

    }

    @objc func cancelClick(textField: UITextField) {
        //textField.resignFirstResponder()
        dateField.resignFirstResponder()
        //dateRegistro.resignFirstResponder()
    }

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    func textFieldDidBeginEditing(_ textField: UITextField) {
        self.createDataPicker(textField)
        //self.createDataPicker(self.dateRegistro)

    }