docs: public static void tagLemma(List<CoreLabel> tokens) {
          // Not sure if this can be static.
          Morphology morpha = new Morphology();
  
          for (CoreLabel token : tokens) {
              String lemma;
              String pos = token.tag();
              if (pos.equals(LangLib.POS_NNPS)) {
                  pos = LangLib.POS_NNS;
              }
              if (pos.length() > 0) {
                  String phrasalVerb = phrasalVerb(morpha, token.word(), pos);
                  if (phrasalVerb == null) {
                      lemma = morpha.lemma(token.word(), pos);
                  } else {
                      lemma = phrasalVerb;
                  }
              } else {
                  lemma = morpha.stem(token.word());
              }
  
              // LGLibEn.convertUnI only accept cap I.
              if (lemma.equals("i")) {
                  lemma = "I";
              }
  
              token.setLemma(lemma);
          }
      }