from pathlib import Path
from datetime import datetime,timezone
import csv,json
p=Path(__file__).parent;r=[]
with (p/'timestamps.csv').open(encoding='utf-8-sig',newline='') as f:
 for a in csv.DictReader(f):
  d=datetime.fromisoformat(a['timestamp'].replace('Z','+00:00'));v='reject_missing_offset' if d.tzinfo is None else d.astimezone(timezone.utc).isoformat().replace('+00:00','Z');assert v==a['expected_utc'];r.append({'id':a['id'],'normalized':v})
assert len({a['normalized'] for a in r[:3]})==1;print(json.dumps(r,indent=2))