/**
* Show the form for creating a new book.
*/
- public function create(string $shelfSlug = null)
+ public function create(?string $shelfSlug = null)
{
$this->checkPermission('book-create-all');
* @throws ImageUploadException
* @throws ValidationException
*/
- public function store(Request $request, string $shelfSlug = null)
+ public function store(Request $request, ?string $shelfSlug = null)
{
$this->checkPermission('book-create-all');
$validated = $this->validate($request, [