private fun displayMonsterList(models: List<MonsterModel>) {
        compositeDisposable.add(
                models.toObservable()
                        .subscribeOn(Schedulers.io())
                        .doOnError { println(it) }
                        .groupBy {
                            it.getName(lang)
                        }
                        .flatmap { mapMonsterGroupToMultiMonster(it) }
                        .observeOn(AndroidSchedulers.mainThread())
                        .subscribeBy {
                            println(it)
                        }
        )
    }

    private fun mapMonsterGroupToMultiMonster(group: GroupedObservable<String, MonsterModel>): MultiMonster {
        return Obervable
               .just(MultiMonster())
               .combinelatest(group,
                   (result, model) -> {
                     run(...);
                     return result;
                   })
               .lastelement()
    }