def twgoExpirationFacts(msg):
    """Used by :func:`twgoExpirationTime` to find latest stop time,
    and if all records have one.

    Finds the latest stop time in a message and also if all
    records have a stop time (if all records don't have a stop
    time, knowing the latest is moot).

    Args:
        msg (dict): Message to be evaluated.

    Returns:
        tuple: Tuple:

        1. (str) Latest stop time in the message. Will return
           ``None`` if there are no stop times in the message.
        2. (bool) ``True`` if all records have a stop time.
           Else ``False``.
    """
    latestStopTime = None
    allRecordsHaveStopTime = True

    if 'geometry' not in msg:
        return (latestStopTime, False)

    geoDicts = msg['geometry']

    for x in geoDicts:
        if 'stop_time' in x:
            if latestStopTime == None:
                latestStopTime = x['stop_time']
            elif x['stop_time'] > latestStopTime:
                # Bonus: ISO datetime sorts correctly as strings!
                latestStopTime = x['stop_time']
        else:
            allRecordsHaveStopTime = False

    return (latestStopTime, allRecordsHaveStopTime)