1from __future__ import annotations23from datetime import UTC, datetime456def utcnow() -> datetime:7 return datetime.now(UTC)8910def iso(dt: datetime | None) -> str | None:11 if dt is None:12 return None13 if dt.tzinfo is None:14 dt = dt.replace(tzinfo=UTC)15 return dt.astimezone(UTC).isoformat().replace("+00:00", "Z")16