@Override
    public PastMeeting getPastMeeting(int id)  {
        Meeting meeting = null;
        PastMeeting pastMeeting = null;
        for (Meeting curr : allMeetings) {
            if (curr.getId() == id) {
                meeting = curr;
            }
        }
        if (meeting instanceof PastMeeting) {
            //down-casting to past meeting
            pastMeeting = (PastMeeting) meeting;

        } else if (meeting instanceof FutureMeeting) {
            /**
             * It is assumed that if a future meeting has gone into the past but has not been converted to a
             * past meeting using addMeetingNotes() yet it will throw an exception
             */
            throw new IllegalArgumentException("This meeting is happening in the future");
        }
        return pastMeeting;
    }