/// <summary>
 /// Time in transit for the shipment.
 /// </summary>
 /// <param name="c"></param>
 /// <returns></returns>
 public RatesArrayFluent <T> DeliveryCommitment(IDeliveryCommitment c)
 {
     _current.DeliveryCommitment = c;
     return(this);
 }
 /// <summary>
 /// If false, the object underlying the interface is not valid. If true, the object may or may not be valid.
 /// </summary>
 /// <param name="d"></param>
 /// <returns></returns>
 public static bool IsValid(IDeliveryCommitment d) => true;