code: @Override
    protected LemmaSample processSample(LemmaSample reference) {
  
      String[] predictedLemmas = lemmatizer.lemmatize(reference.getTokens(), reference.getTags());
      String[] referenceLemmas = reference.getLemmas();
      
      for (int i = 0; i < referenceLemmas.length; i++) {
        //System.err.println("-> Reference: " + referenceLemmas[i]);
        //System.err.println("-> Predicted: " + predictedLemmas[i]);
        if (referenceLemmas[i].equals(predictedLemmas[i])) {
          wordAccuracy.add(1);
        }
        else {
          wordAccuracy.add(0);
        }
      }
      return new LemmaSample(reference.getTokens(), reference.getTags(), predictedLemmas);
    }
docs: Evaluates the given reference {@link LemmaSample} object.
  
  This is done by tagging the sentence from the reference
  {@link LemmaSample} with the {@link Lemmatizer}. The
  tags are then used to update the word accuracy score.
  
  @param reference the reference {@link LemmaSample}.
  
  @return the predicted {@link LemmaSample}.