flow builder and transforming into an Observable

NetworkDataSourceImpl.kt

@ExperimentalCoroutinesApi
override fun search(token: String, query: String)
: Observable<Either<Throwable, List<TweetApiModel>>>
= flow<Either<Throwable, List<TweetApiModel>>> {
    val response = twitterApi.search(
         requestsIOHandler.getTokenFormatted(token), query)
    if (requestsIOHandler.searchIsSuccessful(response)) {
       val tweets = requestsIOHandler.getTweets(response)
       emit(Either.right(tweets))
    } else {
       emit(Either.left(EmptyResponseException()))
    }
}.flowOn(taskThreading.ioDispatcher())
    .asObservable()