name : PortableVisibilityGuard.php <?php declare(strict_types=1); namespace League\Flysystem; final class PortableVisibilityGuard { public static function guardAgainstInvalidInput(string $visibility): void { if ($visibility !== Visibility::PUBLIC && $visibility !== Visibility::PRIVATE) { $className = Visibility::class; throw InvalidVisibilityProvided::withVisibility( $visibility, "either {$className}::PUBLIC or {$className}::PRIVATE" ); } } }