"""时区工具。"""

from __future__ import annotations

from datetime import timedelta, timezone

try:
    from zoneinfo import ZoneInfo
except ImportError:  # pragma: no cover - Python < 3.9 compatibility
    ZoneInfo = None


SHANGHAI_TZ = (
    ZoneInfo("Asia/Shanghai")
    if ZoneInfo is not None
    else timezone(timedelta(hours=8), "Asia/Shanghai")
)