using IcecreamVan.DataModels; namespace IcecreamVan.StoragesContracts; public interface ISaleContract { List GetList(DateTime? startD = null, DateTime? endD = null, string? workerID = null, string? buyerID = null, string? productID = null); SaleDataModel? GetElementById(string id); void AddElement(SaleDataModel saleDataModel); void DelElement(string id); }