code: def play_video(self, video_id, playlist_id=None):
          
          self.start_session_if_none()
          self._session.play_video(video_id, playlist_id)
docs: Play video(video_id) now. This ignores the current play queue order.
          :param video_id: YouTube video id(http://youtube.com/watch?v=video_id)
          :param playlist_id: youtube.com/watch?v=video_id&list=playlist_id