// Using C#, write an extension method that checks if an object is a valid immutable DTO.

// An object is considered a valid DTO if it:

// 1. Does not contain any public or internal fields, except constants;

// 2. Does not contain any public or internal instance properties with public or internal setters;

// 3. Every declared instance property has a public getter.

​

using System;

using System.Collections.Generic;

using System.Linq;

using System.Reflection;

​

var d1 = new PersonDto("Sara", 43);

Console.WriteLine(d1.IsDto()); // returns 'true'

​

var d2 = new SalesOrder();

Console.WriteLine(d2.IsDto()); // returns 'false'

​

// Console.WriteLine(123.IsDto()); // does not compile

// Write your code here:

// --------------------

public class SalesOrder

{

    public string Class; // public fields are not allowed

    public string OrderNbr { get; set; } // public setters are not allowed

    public bool OnHold { internal get; set; } // non-public getters are not allowed

}

​

public class PersonDto

{

    public const double DefaultCreditScore = 100;

​

    public string Name { get; }

    public int? Age { get; }

​

    public PersonDto(string name)

    {

        Name = name;

    }

    public PersonDto(string name, int age)

        : this(name)

    {  

        Age = age;

    }

}

​