/// <summary>
        /// Add two Sufficient Statistics.
        /// </summary>
        /// <param name="stats1">Sufficient Statistics 1.</param>
        /// <param name="stats2">Sufficient Statistics 2.</param>
        /// <returns>Returns the Addition of all.</returns>
        public static StatisticsList Add(SufficientStatistics stats1, SufficientStatistics stats2)
        {
            StatisticsList newList = StatisticsList.GetInstance(stats1);

            newList.Add(stats2);
            return(newList);
        }