for backward compatibility wouldn't it be better to do:

```
sitewide_tz = getattr(settings, 'TIME_ZONE', None)
formatted_string = get_time_display(section['due'], course.due_date_display_format, coerce_tz=settings.TIME_ZONE)
```

This avoids a KeyError on instances where this is not set, ie. existing dev environments, or other people's prod.