public static IQueryable<PetShop.Core.Data.Order> ByBillState(this IQueryable<PetShop.Core.Data.Order> queryable, string billState, params string[] additionalValues)
        {
            var billStateList = new List<string> { billState };

            if (additionalValues != null)
                billStateList.AddRange(additionalValues);

            if (billStateList.Count == 1)
                return queryable.ByBillState(billStateList[0]);

            return queryable.ByBillState(billStateList);
        }
        public static IQueryable<Petshop.Data.Entities.Order> ByBillState(this IQueryable<Petshop.Data.Entities.Order> queryable, System.String billState, params System.String[] additionalValues)
        {
            var billStateList = new List<System.String> { billState };

            if (additionalValues != null)
                billStateList.AddRange(additionalValues);

            if (billStateList.Count == 1)
                return queryable.ByBillState(billStateList[0]);

            return queryable.ByBillState(billStateList);
        }