//public bool IsReadOnly
//{
// get
// {
// throw new NotImplementedException();
// }
//}
//public void Add(MapNode item)
//{
// throw new NotImplementedException();
//}
//public void Clear()
//{
// throw new NotImplementedException();
//}
public bool Contains(MapNode item)
{
return(pendingTasks.Contains(item) || completedTasks.Contains(item));
}
