public static void Edit(ChargeViewModel source, HttpRequestBase request = null)
        {
            Cobro item = Cobro.Get(source.Oid);

            source.CopyTo(item, request);
            item.Save();
        }
        public static void Add(ChargeViewModel item)
        {
            Cobro newItem = Cobro.New();

            item.CopyTo(newItem);
            newItem.Save();
            item.CopyFrom(newItem);
        }