public void UpdateBorrow(int id, Borrow New) => Data.Borrows[id] = New;
public void DeleteBorrow(Borrow id) => Data.Borrows.Remove(id);
//Borrow aka Zdarzenie public void AddBorrow(Borrow borrow) => Data.Borrows.Add(borrow);
//Borrow aka Zdarzenie public void AddBorrow(Borrow borrow) => Data.Borrows.Add(borrow, DateTime.Now);