public IActionResult Run(
            [HttpTrigger(AuthorizationLevel.Anonymous, "get")]
            HttpRequest req)
        {
            var user   = _authService.GetClientPrincipalFromRequest(req);
            var userId = user.UserId;

            if (string.IsNullOrEmpty(userId))
            {
                return(new BadRequestErrorMessageResult("Id cannot be empty"));
            }

            var todoLists = _todoListService.GetListsForUser(userId).ToList();

            return(new OkObjectResult(todoLists));
        }