Ios/swift/ナビゲーションバー/右上にボタンを追加

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   override func viewDidLoad() {
       super.viewDidLoad()
       let rightBookmarkBarButtonItem: UIBarButtonItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Bookmarks, target: self, action: #selector(self.bookmarkButtonTapped))
       self.navigationItem.setRightBarButtonItems([rightBookmarkBarButtonItem], animated: true)
   }
   func bookmarkButtonTapped() {
   }