using System;

using System.Collections.Generic;

​

#nullable enable

public class Program

{

    public static void Main()

    {

        Guid guid = Guid.NewGuid();

        Dictionary<Guid, string> d = new();

        bool found = d.TryGetValue(guid, out string? str);

        if (found is false)

        {

            return;

        }

        string s = str;

    }

}