slarny4/Demo1/Data/Exceptions/UserNotFoundException.cs

// C:\Users\adm\Source\Repos\presence1\Demo\Data\Exceptions\UserNotFoundException.cs
using System;

namespace Demo.Data.Exceptions
{
    public class UserNotFoundException : Exception
    {
        public UserNotFoundException(Guid userId)
            : base($"User with ID {userId} was not found.")
        {
        }
    }
}