.map(Sone::getRootAlbum)
.flatMap(Album::getAlbums)
.flatMap { Album.FLATTENER.apply(it)!! }
.filterNot(Album::isEmpty)
.sortedBy(Album::getTitle)
.also { albums ->
.map(Sone::getRootAlbum)
.flatMap(Album::getAlbums)
.flatMap { Album.FLATTENER.apply(it)!! }
.filterNot(Album::isEmpty)
.sortedBy(Album::getTitle)
.also { albums ->