diff --git a/src/ColumnTogglerTrait.php b/src/ColumnTogglerTrait.php
index 1e3826d..4849729 100644
--- a/src/ColumnTogglerTrait.php
+++ b/src/ColumnTogglerTrait.php
@@ -14,7 +14,7 @@
  */
 trait ColumnTogglerTrait
 {
-    public function serializeForIndex(NovaRequest $request, $fields = null): array
+    public function serializeForIndex(NovaRequest $request, $fields = null)
     {
         $indexFields = $fields ?? parent::indexFields($request);