public static bool IsRetention(this UserOffer offer) => default;
public static bool IsObsolete(this UserOffer offer, DateTime time) => default;
public static bool RetentionPrizeAlreadyTaken(this UserOffer offer, DateTime now) => default;
public static UserOffer AssertOfferHasResourcePrice(this UserOffer offer, bool throwException = true) => default;
public static bool ValidatePurchaseCount(this IEnumerable <DateTime> purchaseDates, PurchaseLimit?limitType, DateTime time, UserOffer offer = null) => default;
public static void AssertOfferPurchaseLimit(this UserOffer offer, DateTime time) { }
public static void AssertOfferPurchaseLimit(this UserOffer userOffer, DateTime time, PurchaseLimit purchaseLimit) { }
public static bool IsFree(this UserOffer offer) => default;