/// <summary>
        /// Get ranked stats. Includes statistics for Twisted Treeline and Summoner's Rift.
        /// </summary>
        private static async Task <IRankedStats> GetRankedStatsSummariesAsync(
            IApiModel leagueModel,
            long summonerId,
            SeasonEnum?season = null,
            RegionEnum?region = null)
        {
            if (leagueModel == null)
            {
                throw new ArgumentNullException("leagueModel");
            }

            var statsService = new StatsService(leagueModel.ApiConfiguration);

            return(await statsService.GetRankedStatsSummariesBySummonerIdAsync(summonerId, season, region));
        }