class ViewController: UIViewController {
    private var ytPlayer: YTPlayerView
    private let stop = UIButton()

    init(ytPlayer: YTPlayerView = YTPlayerView()) {
        self.ytPlayer = ytPlayer    
        super.init(nibName: nil, bundle: nil)
        self.ytPlayer.load(
            withVideoId: "VideoID",
            playerVars: [
                "autoplay": 0,
                "playsinline" : 1,
                "cc_load_policy" : 1,
                "loop" : 1,
                "playlist" : "VideoID",
                "fs": 0])

        stop.addTarget(self, action: #selector(test), for: .touchUpInside)

    }

    @objc func test() {
        ytPlayer.stopVideo()
    }

}