private static List <MeetingData> GetDuplicates(MeetingData meeting, List <MeetingData> meetings) { if (meetings.Count <= 1) { return(null); } return(meetings.FindAll((MeetingData meetingToCheck) => meeting.CalendarItemType == meetingToCheck.CalendarItemType && meeting.GlobalObjectId != null && meetingToCheck.GlobalObjectId != null && GlobalObjectId.Equals(meetingToCheck.GlobalObjectId, meeting.GlobalObjectId))); }