diff --git a/src/WithProductValueMediaFile.php b/src/WithProductValueMediaFile.php
index e99ef79..8a0f010 100644
--- a/src/WithProductValueMediaFile.php
+++ b/src/WithProductValueMediaFile.php
@@ -32,7 +32,7 @@ private function compile(string $code, string $attribute, string $locale = 'null
     /**
      * @return array<string, string>
      */
-    private function evaluate(array $context, string $code, string $attribute, string $locale = 'null', string $scope = 'null'): array
+    private function evaluate(array $context, string $code, string $attribute, string $locale = null, string $scope = null): array
     {
         return [
             'identifier' => $code,