public async Task Verify(Guid circleId, Guid playerId)
        {
            Circle circle = await _circleRepository.FindCircle(circleId);

            if (circle.PlayerId == playerId)
            {
                throw new PlayersMayNotJoinOrBetrayTheirOwnCircleException();
            }
        }
        public async Task Verify(Guid circleId, string key)
        {
            Circle circle = await _circleRepository.FindCircle(circleId);

            if (circle.Key != key)
            {
                throw new CircleKeyMustBeValidInOrderToJoinOrBetrayCircleException();
            }
        }