public Outcome CheckGuess()
        {
            if (CanMakeGuess)
            {
                if (_guessedNumbers.ContainsKey(Guess))
                {
                    return Outcome.OldGuess;
                }
                if (Count == 7)
                {
                    return Outcome.NoMoreGuesses;
                }
                if (_guess == Number)
                {
                    return Outcome.Right;
                }

                else if (_guess > Number)
                {
                    return Outcome.High;
                }
                else if (_guess < Number)
                {
                    return Outcome.Low;
                }
            }
            return Outcome.NoMoreGuesses;
        }