doesntExist() публичный статический Метод

public static doesntExist ( string $class )
$class string
 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);
     }
 }