@Override
  public String toString() {
    return MoreObjects.toStringHelper(this)
        .add("playlists", getPlaylists())
        .add("playlistItems", getPlaylistItems())
        .add("tracks", getTracks())
        .add("releases", getReleases())
        .toString();
  }
A Wrapper for a group of music entities.
portability-types-common/src/main/java/org/datatransferproject/types/common/models/music/MusicContainerResource.java