code: @Override
    protected FeatureSample processSample(FeatureSample reference) {
      String[] predictedFeatures = featurizer.featurize(reference.getSentence(),
          reference.getTags());
      String[] referenceTags = reference.getFeatures();
  
      for (int i = 0; i < referenceTags.length; i++) {
        if (referenceTags[i].equals(predictedFeatures[i])) {
          wordAccuracy.add(1);
        } else {
          wordAccuracy.add(0);
        }
      }
  
      FeatureSample result = new FeatureSample(reference.getSentence(), reference.getLemmas(),
          reference.getTags(), predictedFeatures);
  
      return result;
    }
docs: Evaluates the given reference {@link FeatureSample} object.
  
  This is done by finding the phrases with the {@link Featurizer} in the
  sentence from the reference {@link FeatureSample}. The found phrases are
  then used to calculate and update the scores.
  
  @param reference
  the reference {@link FeatureSample}.
  
  @return the predicted sample