public void DeleteSmartLockUser(Guid smartLockId, Guid userId)
        {
            if (smartLockId == Guid.Empty)
            {
                throw new ArgumentNullException(nameof(smartLockId));
            }

            if (userId == Guid.Empty)
            {
                throw new ArgumentNullException(nameof(userId));
            }

            var smartLockUser = new SmartLockUser {
                SmartLockId = smartLockId, UserId = userId
            };

            _context.Remove(smartLockUser);
        }
        public void AddSmartLockUser(Guid smartLockId, Guid userId)
        {
            if (smartLockId == Guid.Empty)
            {
                throw new ArgumentNullException(nameof(smartLockId));
            }

            if (userId == Guid.Empty)
            {
                throw new ArgumentNullException(nameof(userId));
            }

            var smartLockUser = new SmartLockUser
            {
                UserId      = userId,
                SmartLockId = smartLockId
            };

            _context.Add(smartLockUser);
        }