Использование оператора new

https://docs.microsoft.com/en-us/previous-versions/ms379574(v=vs.80)

ссылка на статью

public class GraphNode<T> : Node<T>
{
    private List<int> costs;
    public GraphNode() : base() { }
    public GraphNode(T value) : base(value) { }
    public GraphNode(T value, NodeList<T> neighbors) : base(value, neighbors) { }
    new public NodeList<T> Neighbors // зачем здесь new?
    {
        get
        {
            if (base.Neighbors == null)
                base.Neighbors = new NodeList<T>();
            return base.Neighbors;
        }            
    }
    public List<int> Costs
    {
        get
        {
            if (costs == null)
                costs = new List<int>();
            return costs;
        }
    }
}