Elegant way to chain Completables

Question

How to chain Completables in a more elegant way? .toSingleDefault(0) seems to be hacky

Single.just(newGroup)
.flatMapCompletable {
    dao.delete(currentGroup)
}
.toSingleDefault(0)
.flatMapCompletable {
     dao.insert(newGroup)
}

Answer 1

I tried before

Single.just(newGroup)
    .flatMapCompletable {
        dao.delete(currentGroup)
    }
    .andThen {
        dao.insert(newGroup)
    }

and it didn't work without explicit .subscribe(), but calling it in () like

Single.just(newGroup)
    .flatMapCompletable {
        dao.delete(currentGroup)
    }
    .andThen (
        dao.insert(newGroup)
    )

will subscribe it automatically