public bool Equals(AvailableCar other)
 {
     if (other == null)
     {
         return(false);
     }
     return(this.total_time.Equals(other.total_time));
 }
        // Default comparer for Part type.
        public int CompareTo(AvailableCar compareTime)
        {
            // A null value means that this object is greater.
            if (compareTime == null)
            {
                return(1);
            }

            else
            {
                return(this.total_time.CompareTo(compareTime.total_time));
            }
        }