'Return a tuple of the playlist\'s video ids and exercise ids as sets'

@classmethod
def get_playlist_entry_ids(cls, playlist):

    items = get_topic_contents(topic_id=playlist.get('id'))
    pl_video_ids = set([item.get('id') for item in items if (item.get('kind') == 'Video')])
    pl_exercise_ids = set([item.get('id') for item in items if (item.get('kind') == 'Exercise')])
    return (pl_video_ids, pl_exercise_ids)
