Function arguments typo?

This is the lesson:

It says current_books.extend(), and I don’t remember there being a .extend() for lists. The correct solution is to use .append(), but I have a feeling that it might confuse some people. Was this an accident or on purpose?

If it’s wrong then how does it misbehave if you run it?

What do you expect it to do?
What should it do instead?
What does it do?

Huh. I just changed it and now it works. Disregard everything I just said :sweat_smile: