fileprivate func addBarButton() {
    if tableView.isEditing {
        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .done, target: self, action: #selector(editButtonAction))
    } else {
        navigationItem.rightBarButtonItem = UIBarButtonItem(barButtonSystemItem: .edit, target: self, action: #selector(doneButtonAction))
    }
}


@objc func editButtonAction(sender: UIBarButtonItem) {
    tableView.isEditing = !tableView.isEditing
}



@objc func doneButtonAction(sender: UIBarButtonItem) {
    tableView.isEditing = !tableView.isEditing
}

override func viewDidLoad() {
    super.viewDidLoad()
    addBarButton()
    tableView?.isEditing = true
}