Observable.fromCallable() method inside not getting called

This is how i'm using the Observable.fromCallable(). In other classes its working fine, but not in some of the classes. Any help would be appreciated.

Observable
.fromCallable(() ->
    getWorkTypeId(tem.getId(), tem.getTypeId())
    .flatMap(oldEntities -> 
        replaceTempAuth(tem.getId(), tem.getTypeId(), 
           getTemes(tem, oldEntities), oldEntities
        )
    )
    .flatMap(deletedEntities -> 
        deleteAllWithId(deletedEntities.stream()
                       .map(TempEntity::getTemId)
                       .collect(Collectors.toList()), tem.getId())
    )
);

Here replaceTempAuth method and deleteAllWithId is not getting called.

Got the answer from @kristyWelsh Added .subscribe() works perfectly.