public ISong getSong() {
    if (type == SPOTIFY) {
      return JSONUtils.GSON.fromJson(json, SpotifySong.class);
    } else if (type == LOCAL) {
      return JSONUtils.GSON.fromJson(json, Song.class);
    } else if (type == SOUND_CLOUD) {

    }
    return null;
  }
  @Override
  public String toString() {

    return JSONUtils.GSON.toJson(this);
  }