|> Enum.map(fn stream -> stream |> Stream.take(20) |> Enum.to_list() end)

    |> Stream.map(&collect_sentences/1)
    |> Enum.map(fn stream -> stream |> Stream.take(50) |> Enum.to_list() end)

  defp collect_sentences(stream) do
    stream |> Stream.transform(
      [],
      fn
        {:line, line}, acc ->
        splitted = line
        |> String.split(".")
        case splitted do
          [p] -> {[], [p|acc]}
          _ ->
            last = List.last(splitted)
            first_sentence = [List.first(splitted) | acc]
            |> Enum.reverse
            |> Enum.join(" ")
            other_sentences = splitted
            |> Enum.drop(1)
            |> Enum.drop(-1)
            |> Enum.map(fn s -> {:sentence, s} end)
            new_acc = if last == "" do
              []
            else
              [last]
            end
            {[{:sentence, first_sentence}] ++ other_sentences, new_acc}
        end
        a, acc -> {[a], acc}
      end
    )
  end