@futurebird "My code isn't working!" "Why?"
I realize that's a flip response to your inquiry, but, ultimately it is what you're looking to enable your students to do, right? They should be able to say more than "it isn't working" which is uninformative. So, it isn't working .. what else can you say about what is - or isn't - happening and what hypothesis can you give as to why? And if you have a hypothesis, how can you test it?