执行 Ruff 安全自动修复

web/backend/services/yyb_service.py

@@ -2,7 +2,7 @@
 
 from __future__ import annotations
 
-from datetime import datetime, timezone
+from datetime import UTC, datetime
 from typing import Any
 
 from sqlalchemy.orm import Session
@@ -12,12 +12,12 @@ from .yyb_worker_client import YybWorkerClient
 
 
 def _utcnow():
-    return datetime.now(timezone.utc)
+    return datetime.now(UTC)
 
 
 def _from_ts(value) -> datetime | None:
     try:
-        return datetime.fromtimestamp(int(value), tz=timezone.utc) if value else None
+        return datetime.fromtimestamp(int(value), tz=UTC) if value else None
     except (TypeError, ValueError, OSError):
         return None
 
@@ -27,8 +27,8 @@ def _as_utc(value: datetime | None) -> datetime | None:
     if value is None:
         return None
     if value.tzinfo is None:
-        return value.replace(tzinfo=timezone.utc)
-    return value.astimezone(timezone.utc)
+        return value.replace(tzinfo=UTC)
+    return value.astimezone(UTC)
 
 
 def cleanup_orphan_yyb_tasks(db: Session, message: str) -> int: