public void MoveToNextColumn(Ticket ticket) { Guard.ArgumentNotNull(nameof(ticket), ticket); if (Backlog.Contains(ticket)) { Move(Backlog, ToDo, ticket); return; } if (ToDo.Contains(ticket)) { Move(ToDo, Test, ticket); return; } if (Test.Contains(ticket)) { Move(Test, Done, ticket); return; } if (Done.Contains(ticket)) { throw new InvalidOperationException("The ticket is in the done column"); } throw new InvalidOperationException("Ticket not found"); }