code: @Override
      public void printGroundtruth(final Long user, final PrintStream out, final OUTPUT_FORMAT format) {
          final Map<Long, Double> relItems = new HashMap<Long, Double>();
          for (Long i : test.getUserItems(user)) {
              Double d = test.getUserItemPreference(user, i);
              if (d >= threshold) {
                  relItems.put(i, d);
              }
          }
          printGroundtruth("" + user, relItems, out, format);
      }
docs: {@inheritDoc}