Poker.PokerHandsChecker.IsFourOfAKind C# (CSharp) Method

        public bool IsFourOfAKind(IHand hand)
        {
            if (!this.IsValidHand(hand))
            {
                throw new ArgumentException("Hand was not valid");
            }

            bool isFourOfAKind = false;
            int count = 1;
            int bestCount = int.MinValue;
            int cardsInHand = hand.Cards.Count;

            for (int i = 0; i < cardsInHand; i++)
            {
                for (int j = i + 1; j < cardsInHand; j++)
                {
                    if (hand.Cards[i].Face == hand.Cards[j].Face)
                    {
                        count++;
                    }
                }

                if (count == 4)
                {
                    break;
                }

                count = 1;
            }

            if (count == 4)
            {
                isFourOfAKind = true;
            }

            return isFourOfAKind;
        }

        private static void Main()
        {
            try
            {
                IHand hand = new Hand(new List<ICard>() 
                { 
                    new Card(CardFace.Ace, CardSuit.Clubs),
                    new Card(CardFace.Queen, CardSuit.Clubs),
                    new Card(CardFace.King, CardSuit.Clubs),
                    new Card(CardFace.Jack, CardSuit.Clubs),
                    new Card(CardFace.Ten, CardSuit.Clubs),
                });
                Console.WriteLine(hand);
                IPokerHandsChecker checker = new PokerHandsChecker();

                Console.WriteLine(checker.IsValidHand(hand) ? "Hand is valid." : "Hand is not valid!");
                Console.WriteLine(checker.IsRoyalFlush(hand) ? "Royal flush." : "Hand is not Royal flush!");
                Console.WriteLine(checker.IsStraightFlush(hand) ? "Straight flush." : "Hand is not Straight flush!");
                Console.WriteLine(checker.IsFlush(hand) ? "Flush." : "Hand is not Flush!");
                Console.WriteLine(checker.IsStraight(hand) ? "Straight." : "Hand is not Straight!");
                Console.WriteLine(checker.IsFullHouse(hand) ? "Full house." : "Hand is not Full house!");
                Console.WriteLine(checker.IsFourOfAKind(hand) ? "Four of a kind." : "Hand is not Four of a kind!");
                Console.WriteLine(checker.IsThreeOfAKind(hand) ? "Three of a kind." : "Hand is not Three of a kind!");

                IHand hand1 = new Hand("K♥ J♥ 8♣ 7♦ 4♠");
                Console.WriteLine(hand1);
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }