def METHOD_NAME(replay_start, timestamp):
    if len(timestamp.split(".")[-1]) < 6:
        for i in range(6 - len(timestamp.split(".")[-1])):
            timestamp = timestamp + "0"
    start = datetime.fromisoformat(replay_start)
    stamp = datetime.fromisoformat(timestamp)
    if start.tzinfo is None:
        start = start.replace(tzinfo=timezone.utc)
    if stamp.tzinfo is None:
        stamp = stamp.replace(tzinfo=timezone.utc)
    return ((stamp - start).total_seconds()) * 1000