Chapter 2 error (Help)

[DracotMolver]

I'm doing the same thing (I bought the book), but when I was adding the business logic to the buttons, I've got the next error:
AttributeError: 'todo.task' object has no attribute 'do_toggle_done'
I've got the same code like you.
Do you know why this happen?. Any help, is welcome :). Thanks

[DracotMolver]

duh!, It was my mistake. I didn't add the secutity rules :P