<s>[INST] class Tutor:

 

    def practice(self):
 

         study_item = study_items.pop(0) + '/' + study_item

Can you spot the bug?
Yes. The variable `study_items` is being called without being declared anywhere else in the class. Even worse, study_items is no where to be seen within the class. Look to declare a variable within the class rather than calling one that doesn't belong.[/INST]