code: public String toPOSString(char delimiter) {
        return tokens()
                  .stream()
                  .map(t -> t.toString() + delimiter + t
                                                          .get(Types.PART_OF_SPEECH)
                                                          .as(POS.class, POS.ANY)
                                                          .asString())
                  .collect(Collectors.joining(" "));
     }
docs: Converts the HString to a string with part-of-speech information attached using the given delimiter
  
  @param delimiter the delimiter to use to separate word and part-of-speech
  @return the HString with part-of-speech information attached to tokens