Option Type for C#

Option.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace OptionType
{
    public abstract class Option<T>
    {
        public abstract T Value { get; }
        public abstract bool IsEmpty { get; }

        public Option<TRet> Bind<TRet>(Func<T, TRet> fun)
        {
            if (IsEmpty)
            {
                return None<TRet>.INSTANCE;
            }
            return fun(Value).AsOption();
        }

        public void Bind(Action<T> fun)
        {
            if (!IsEmpty)
            {
                fun(Value);
            }
        }

        public T GetOrElse(T defaultValue)
        {
            if (IsEmpty)
            {
                return defaultValue;
            }

            return Value;
        }
    }

    public static class Options
    {
        public static Option<TOption> AsOption<TOption>(this TOption value)
        {
            if (value == null)
            {
                return None<TOption>.INSTANCE;
            }

            return new Some<TOption>(value);
        }
    }

    public sealed class Some<T> : Option<T>
    {
        private readonly T value;

        public Some(T value)
        {
            if (value == null)
            {
                throw new ArgumentNullException("value", "value is expected - use None instead of Some");
            }
            this.value = value;
        }

        public override T Value
        {
            get { return value; }
        }

        public override bool IsEmpty
        {
            get { return false; }
        }
    }

    public sealed class None<T> : Option<T>
    {
        internal static readonly None<T> INSTANCE = new None<T>();

        public override T Value
        {
            get { throw new NotSupportedException("No value available"); }
        }

        public override bool IsEmpty
        {
            get { return true; }
        }
    }
}