public static string Compute(long accountId, string userId)
        {
            var accountIdAsString = accountId.ToString();
            var vwoNamespaceGuid  = Identifiable.NamedGuid.Compute(NamedGuidAlgorithm.SHA1, UrlNamespace, VWO_NAMESPACE_URL);
            var accountIdGuid     = NamedGuid.Compute(NamedGuidAlgorithm.SHA1, vwoNamespaceGuid, accountIdAsString);
            var userIdGuid        = NamedGuid.Compute(NamedGuidAlgorithm.SHA1, accountIdGuid, userId);
            var uuid = userIdGuid.ToString(GUID_FORMAT).ToUpper();

            LogDebugMessage.UuidForUser(file, userId, accountId, uuid);
            return(uuid);
        }