diff --git a/optuna_dashboard/_form_widget.py b/optuna_dashboard/_form_widget.py
index ee79e52b..2d6809ab 100644
--- a/optuna_dashboard/_form_widget.py
+++ b/optuna_dashboard/_form_widget.py
@@ -224,8 +224,8 @@ class TextInputWidget:
 class ObjectiveUserAttrRef:
     """
     A class representing a reference to a value of `trial.user_attrs`.
-    When combined with `register_objective_form_widgets`, users can tell values that are registered to
-    `trial.user_attrs` during the human-in-the-loop optimization.
+    When combined with `register_objective_form_widgets`, users can tell values that are
+    registered to `trial.user_attrs` during the human-in-the-loop optimization.
 
     Args:
         key: The key of `trial.user_attrs` being referenced.