public static Polyface IsDatedExpirable(this Polyface root, DateTime expiry)
 {
     Condition.Requires(root).IsNotNull();
     var composited = new NaturalDatedExpirable(expiry);
     root.Is(composited);
     return root;
 }
        public static Polyface IsDatedExpirable(this Polyface root, DateTime expiry)
        {
            Condition.Requires(root).IsNotNull();
            var composited = new NaturalDatedExpirable(expiry);

            root.Is(composited);
            return(root);
        }