code: public int compareTo(WordLemmaTag wordLemmaTag) {
      int first = word().compareTo(wordLemmaTag.word());
      if (first != 0)
        return first;
      int second = lemma().compareTo(wordLemmaTag.lemma());
      if (second != 0)
        return second;
      else
        return tag().compareTo(wordLemmaTag.tag());
    }
docs: Orders first by word, then by lemma, then by tag.
  
  @param wordLemmaTag object to compare to
  @return result (positive if <code>this</code> is greater than
  <code>obj</code>, 0 if equal, negative otherwise)