private static async Task<IEnumerable<ILeague>> RetrievesLeaguesDataAsync(
            IApiModel leagueModel,
            long summonerId,
            RegionEnum? region = null)
        {
            if (leagueModel == null) throw new ArgumentNullException("leagueModel");

            var leagueService = new LeagueService(leagueModel.ApiConfiguration);
            return await leagueService.RetrievesLeaguesDataForSummonerAsync(summonerId, region);
        }