public function reverseTransform($value): ?User
    {
        if (empty($value)) {
            return null;
        }

        if (!is_numeric($value)) {
            throw new TransformationFailedException('Expected a numeric string.');
        }

        try {
            return $this->userService->loadUser($value);
        } catch (NotFoundException $e) {
            throw new TransformationFailedException($e->getMessage(), $e->getCode(), $e);
        }
    }