def _start_time_from_groupdict(groupdict):
    """Convert the argument hour/minute/seconds minute into a millisecond value.

    """
    if groupdict['hours'] is None:
        groupdict['hours'] = 0
    return (int(groupdict['hours']) * 3600 +
            int(groupdict['minutes']) * 60 +
            int(groupdict['seconds'])) * 1000