Test optional monad with C# 7 pattern matching

OptionalTest.cs

using System;

namespace MonadTest
{
    public interface IOptional<T> where T : class
    {
        T Value { get; }
    }

    public abstract class Optional<T> : IOptional<T>
        where T : class
    {
        public abstract T Value { get; }

        public static IOptional<T> Some(T value) => new Some<T>(value);
        public static IOptional<T> None() => new None<T>();
    }

    public sealed class Some<T> : Optional<T>
        where T : class
    {
        public override T Value { get; }
        public Some(T value)
        {
            Value = value;
        }
    }

    public sealed class None<T> : Optional<T>
        where T : class
    {
        public override T Value => throw new NotSupportedException();
    }
    
     class Person
    {
        public Person(string name, string surname)
        {
            Name = name;
            Surname = surname;
        }

        public string Name { get; set; }
        public string Surname { get; set; }
    }

    class Program
    {
        public static IOptional<Person> GetPerson(bool isSome) 
        => isSome ?
            Optional<Person>.Some(new Person("Adam", "Kowalski")) :
            Optional<Person>.None();

        static void Main(string[] args)
        {
            var opt = GetPerson(false);

            switch (opt)
            {
                case Some<Person> p:
                    Console.WriteLine($"{p.Value.Name} {p.Value.Surname} is present");
                    break;
                case None<Person> n:
                    Console.WriteLine("No one is present");
                    break;
            }
        }
    }
}