diff --git a/spec.bs b/spec.bs
index 276c4dd..94859ca 100644
--- a/spec.bs
+++ b/spec.bs
@@ -159,7 +159,7 @@ interface StorageAccessHandle {
 
 partial interface Document {
   Promise<boolean> hasUnpartitionedCookieAccess();
-  Promise<StorageAccessHandle> requestStorageAccess(StorageAccessTypes types);
+  Promise<StorageAccessHandle> requestStorageAccess(optional StorageAccessTypes types = {});
 };
 </pre>