fix by lint

optuna_dashboard/_serializer.py

@@ -173,14 +173,14 @@ def serialize_study_detail(
 
 def serialize_preference_history(
     system_attrs: dict[str, Any],
-) -> list[History]:
-    histories: list[History] = []
+) -> list[dict[str, Any]]:
+    histories: list[dict[str, Any]] = []
     for k, v in system_attrs.items():
         if not k.startswith(_SYSTEM_ATTR_PREFIX_HISTORY):
             continue
         choice: dict[str, Any] = json.loads(v)
         if choice["mode"] == "ChooseWorst":
-            history: ChooseWorstHistory = {
+            history = {
                 "mode": "ChooseWorst",
                 "id": choice["id"],
                 "preference_id": choice["preference_id"],

python_tests/test_preferential_history.py

@@ -71,7 +71,7 @@ def test_undo_redo_history(storage_supplier: Callable[[], StorageSupplier]) -> N
 
         study_id = study._study._study_id
 
-        def get_preferences_history(history_id: str):
+        def get_preferences_history(history_id: str) -> tuple[list[tuple[int, int]], History]:
             system_attrs = storage.get_study_system_attrs(study_id)
             history: History = json.loads(
                 system_attrs.get(_SYSTEM_ATTR_PREFIX_HISTORY + history_id, "")