diff --git a/packages/file-bundle/src/DependencyInjection/RekalogikaFileExtension.php b/packages/file-bundle/src/DependencyInjection/RekalogikaFileExtension.php
index 5e82784..b7281ca 100644
--- a/packages/file-bundle/src/DependencyInjection/RekalogikaFileExtension.php
+++ b/packages/file-bundle/src/DependencyInjection/RekalogikaFileExtension.php
@@ -120,7 +120,7 @@ public function load(array $configs, ContainerBuilder $container): void
             ->addTag('rekalogika.file.association.object_id_resolver');
     }
 
-    public function prepend(ContainerBuilder $container)
+    public function prepend(ContainerBuilder $container): void
     {
         if (
             class_exists(EmbeddedMetadata::class)