code: @Override
    public ListSufficientStatistics getNewSufficientStatistics() {
      List<SufficientStatistics> sufficientStatistics = Lists.newArrayList();
      for (ParametricFactor factor : getParametricFactors()) {
        sufficientStatistics.add(factor.getNewSufficientStatistics());
      }
      return new ListSufficientStatistics(factorNames.items(), sufficientStatistics);
    }
docs: {@inheritDoc}
  <p>
  The returned statistics have names corresponding to the
  parametric factors in this. That is, the parameters for a
  particular parametric factor in this factor graph can be
  retrieved using
  {@link ListSufficientStatistics#getStatisticByName(String)}.
  
  @return