the story does't displayed when i press the 'Start your Adventure' button??

override func viewDidLoad() {
        super.viewDidLoad()


        if let page = page{

            artworkView.image = page.story.artWork
            let attributedString = NSMutableAttributedString(string: page.story.text)
            let paragraphStyle = NSMutableParagraphStyle()
            paragraphStyle.lineSpacing = 10

            attributedString.addAttribute(NSParagraphStyleAttributeName, value: paragraphStyle, range: NSMakeRange(0, attributedString.length))






            storyLabel.text   = page.story.text
        }




  override func viewWillLayoutSubviews() {
        super.viewWillLayoutSubviews()

        view.addSubview(artworkView)
        artworkView.translatesAutoresizingMaskIntoConstraints = false // to cannot makes conflict in constraints when the new sub view added

        // image constraint
        NSLayoutConstraint.activate([
            artworkView.topAnchor.constraint(equalTo: view.topAnchor),
            artworkView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
            artworkView.rightAnchor.constraint(equalTo: view.rightAnchor),
            artworkView.leftAnchor.constraint(equalTo: view.leftAnchor)

            ])
        // label constraints
        view.addSubview(storyLabel)
        storyLabel.numberOfLines = 0
        storyLabel.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            storyLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 16.0),
            storyLabel.trailingAnchor.constraint(equalTo: view.trailingAnchor, constant: -16.0),
            storyLabel.topAnchor.constraint(equalTo: view.topAnchor, constant: -48.0)

            ])





    }