Nitpick: this might be better as:
```python
if callable(getattr(self, runtime, "get_real_user", None)):
    self.user = self.runtime.get_real_user(self.runtime.anonymous_student_id).email
else:
    self.user = None
```

Also, it looks like you're storing the email address, not an actual user object. Would it make more sense to store this value to `self.user_email` instead of `self.user`?