Error using Inertia::Share in AppServiceProvider

Hi Everyone, I am having an issue using Inertia::share in AppServiceProvider. The following code produces this error:

namespace App\Providers;
use Illuminate\Support\ServiceProvider;
class AppServiceProvider extends ServiceProvider
{
    public function register() {
         Inertia::share(function () {
            return ['app' => ['sitename' => config('app.name')]];
        });
    }
    public function boot() {
        Inertia::share([
            'locale' => function () {
                return app()->getLocale();
            },
            'language' => function () {
                return translations(
                    resource_path('lang/'. app()->getLocale() .'.json')
                );
            },
        ]);
    }
}

Error in artisan below:

  Class 'App\Providers\Inertia' not found

  at app/Providers/AppServiceProvider.php:15
     11▕      *
     12▕      * @return void
     13▕      */
     14▕     public function register() {
  ➜  15▕          Inertia::share(function () {
     16▕             return ['app' => ['sitename' => config('app.name')]];
     17▕         });
     18▕     }
     19▕     /**

      +7 vendor frames
  8   artisan:37
      Illuminate\Foundation\Console\Kernel::handle()

If I remove the Inertia::share calls, then there are no errors in artisan. Any ideas why this could cause this error?