There's *way* too much logic happening on one line here. Also, I doubt you need to use a regular expression here -- why not just check if the string starts with "instructor_" or "staff_", and if so, slice it off? Something like this:
```python
if user_staff_group_name.startswith("instructor_"):
    user_staff_group_name = user_staff_group_name[11:]
elif user_staff_group_name.startswith("staff_"):
    user_staff_group_name = user_staff_group_name[6:]
```
It uses more lines of code, but it's clearer to read and faster to execute.