protocol View: class {
    func show(data: String)
}

class ViewController: UIViewController, View {

    let presenter: Presenter
    var label: UILabel!

    init(presenter: Presenter) {
        self.presenter = presenter
        super.init(nibName: nil, bundle: nil)
    }

    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

    func show(data: String) {
        label.text = data
    }

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