lab3/model/Class5.cs

using System;
using WpfApp1;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.Text;
using System.Threading.Tasks;

namespace WpfApp1.model
{
    [DataContract]
    public class CarWithStringDates : cars
    {
        [DataMember]
        public string? dateOfLastSTO { get; set; }
    }
}