public void UnlinkDevice(string userId, string deviceId)
        {
            Guid deviceGuid;

            if (!Guid.TryParse(deviceId, out deviceGuid))
            {
                throw new ArgumentException("Invalid device ID format.");
            }
            var request = new DirectoryV3DevicesDeleteRequest(userId, deviceGuid);

            _transport.DirectoryV3DevicesDelete(request, _directoryId);
        }