public StandingsResponse Create(Tournament tournament, int?roundNumber)
        {
            if (tournament == null)
            {
                throw new ArgumentNullException("tournament");
            }

            var playerStandings = tournament
                                  .Players
                                  .Select(player => new
            {
                name                        = player.Name,
                matchPoints                 = StatsProvider.GetMatchPoints(tournament, player, roundNumber),
                matchWinPercentage          = StatsProvider.GetMatchWinPercentage(tournament, player, roundNumber),
                opponentsMatchWinPercentage = StatsProvider.GetOpponentsMatchWinPercentage(tournament, player, roundNumber),
                gamePoints                  = StatsProvider.GetGamePoints(tournament, player, roundNumber),
                gameWinPercentage           = StatsProvider.GetGameWinPercentage(tournament, player, roundNumber),
                opponentsGameWinPercentage  = StatsProvider.GetOpponentsGameWinPercentage(tournament, player, roundNumber),
            })
                                  .OrderByDescending(o => o.matchPoints)
                                  .ThenByDescending(o => o.opponentsMatchWinPercentage)
                                  .ThenByDescending(o => o.gameWinPercentage)
                                  .ThenByDescending(o => o.opponentsGameWinPercentage)
                                  .Select((o, rank) => new PlayerStandingResponse(
                                              rank: rank + 1,
                                              playerName: o.name,
                                              matchPoints: o.matchPoints,
                                              matchWinPercentage: o.matchWinPercentage,
                                              opponentsMatchWinPercentage: o.opponentsMatchWinPercentage,
                                              gamePoints: o.gamePoints,
                                              gameWinPercentage: o.gameWinPercentage,
                                              opponentsGameWinPercentage: o.opponentsGameWinPercentage
                                              ))
                                  .ToArray();

            return(new StandingsResponse(playerStandings));
        }