src/Controller/FileUpload.php | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Controller/FileUpload.php b/src/Controller/FileUpload.php
index b4c7e0e..52f7bdb 100644
--- a/src/Controller/FileUpload.php
+++ b/src/Controller/FileUpload.php
@@ -193,7 +193,8 @@ class FileUpload {
     /* $self_link = new Link(new CacheableMetadata(), $this->entity->toUrl('jsonapi'), ['self']); */
     $links = new LinkCollection(['self' => $self_link]);
 
-    $file_resource_type = reset($resource_type->getRelatableResourceTypesByField($file_field_name));
+    $relatable_resource_types = $resource_type->getRelatableResourceTypesByField($file_field_name);
+    $file_resource_type = reset($relatable_resource_types);
     return new ResourceResponse(new JsonApiDocumentTopLevel(new ResourceObject($file_resource_type, $file), new NullEntityCollection(), $links), 201, []);
   }