code: public static function getDefaultPriceMapLoader()
      {
          if (null === self::$defaultPriceMapLoader) {
              $currencyDir = realpath(__DIR__ . '/../../../data/prices');
  
              self::$defaultPriceMapLoader = new PhpFileLoader(array($currencyDir));
          }
  
          return self::$defaultPriceMapLoader;
      }
docs: Get default price map loader
  
  @return LoaderInterface