public CopyStatus RentCopy(string copyCode, string userCode)
        {
            Copy copyToRent = GetCopy(copyCode);
            if(copyToRent == null)
                throw new Exception("Brak egzemplarza o taki numerze!");

            if (!copyToRent.Condition.Equals(Conditions.Avaliable))
                throw new Exception("Egzemplarz niedostępny do wypożyczenia!");

            User rentingUser = GetUser(userCode);
            if(rentingUser == null)
                throw new Exception("Brak uzytkownika o danym numerze!");

            CopyStatus copyToReturn = new CopyStatus();
            copyToReturn.RentTime = DateTime.Now;
            copyToReturn.ReturnTime = (DateTime.Now).AddMonths(1);
            copyToReturn.RentBy = rentingUser;
            copyToReturn.DaysDelay = 0;
            copyToReturn.Copy = copyToRent;

            if(InsertNewCopyStatus(copyToReturn))
                return copyToReturn;
            return null;
        }
 public bool InsertNewCopyStatus(CopyStatus statusToInsert)
 {
     return true;
 }
 public void DeleteCopyStatus(CopyStatus copyStatus)
 {
 }