diff --git a/core/modules/system/src/Controller/CssAssetController.php b/core/modules/system/src/Controller/CssAssetController.php
index 112dbfb..b5d4dc5 100644
--- a/core/modules/system/src/Controller/CssAssetController.php
+++ b/core/modules/system/src/Controller/CssAssetController.php
@@ -41,7 +41,7 @@ public static function create(ContainerInterface $container) {
   /**
    * {@inheritdoc}
    */
-  protected function getKeyAndGroup(AttachedAssetsInterface $attached_assets, $group_delta, $request) {
+  protected function getGroup(AttachedAssetsInterface $attached_assets, $group_delta, $request) {
     $assets = $this->assetResolver->getCssAssets($attached_assets, FALSE);
 
     // Group the assets.