Spatie\MediaLibrary\Exceptions\InvalidUrlGenerator::doesntExist PHP Метод

    public static function doesntExist(string $class)
    {
        return new static("Class {$class} doesn't exist");
    }

 public static function guardAgainstInvalidUrlGenerator(string $urlGeneratorClass)
 {
     if (!class_exists($urlGeneratorClass)) {
         throw InvalidUrlGenerator::doesntExist($urlGeneratorClass);
     }
     if (!is_subclass_of($urlGeneratorClass, UrlGenerator::class)) {
         throw InvalidUrlGenerator::isntAUrlGenerator($urlGeneratorClass);
     }
 }