public function transform($value): ?string
    {
        if (null === $value) {
            return null;
        }

        if (!is_array($value) || array_diff(['id', 'module', 'function'], array_keys($value))) {
            throw new TransformationFailedException('Expected a valid array of data.');
        }

        return implode(':', [$value['id'], $value['module'], $value['function']]);
    }