public static bool IsEmpty(this GiveOfferDto offer) => default;
// Extension methods public static UserOffer AddOffer(this UserOfferData userData, GiveOfferDto giveOffer, DateTime givenTime, DateTime?validTill) => default;
public static bool IsEmpty(this GiveOfferDto offer) => default;
// Extension methods public static UserOffer AddOffer(this UserOfferData userData, GiveOfferDto giveOffer, DateTime givenTime, DateTime?validTill) => default;