open class VideoPlayerPresenter{
  private var View view
  internal var volumeListener VolumeListener? = null

  override fun setView(view: View) {
    this.view = view
  }

  fun setMuted(player: Player?, isMuted: Boolean){
    player?.setVolume(if(isMuted) 0f else 1f)
    volumeListener.onMuteStateChanged(isMuted)
  }

  fun setVolume(player: Player?, volume: Float){
    player?.setVolume(volume)
    volumeListener.onVolumeChanged(volume)
  }

  interface View: BaseView{
    ...
  }
}