code: public double score(List<L> guesses, List<L> trueLabels) {
      clearCounts();
      addGuesses(guesses, trueLabels);
      finalizeCounts();
      return getFMeasure();
    }
docs: Returns the score (F1) for the given list of guesses
  @param guesses - Guesses by classifier
  @param trueLabels - Gold labels to compare guesses against
  @return F1 score