public void AddEvent(EventRow @event)
        {
            if (@event == null)
            {
                throw new ArgumentNullException(nameof(@event));
            }

            if (@event.Id == null || this.events.ContainsKey(@event.Id))
            {
                return;
            }

            this.events.Add(@event.Id, @event);
        }
 public static bool IsNullOrNone(this EventRow self)
 => self == null || self == EventRow.None;