BusinessLogic.Logic.Points.PointsCalculator.ValidatePlayerRanks C# (CSharp) Метод

        private static void ValidatePlayerRanks(IList<PlayerRank> playerRanks)
        {
            if (playerRanks.Count > FIBONACCI_N_PLUS_2.Count)
            {
                throw new ArgumentException(EXCEPTION_MESSAGE_CANNOT_EXCEED_MAX_PLAYERS);
            }

            if (playerRanks.GroupBy(x => x.PlayerId).Count(y => y.Count() > 1) > 0)
            {
                throw new ArgumentException(string.Format(EXCEPTION_MESSAGE_DUPLICATE_PLAYER));
            }
        }