[web2py] ASK Web2py Groups:Is there a better way?

[Pystar]

In an app I am developing, in my database definition I have a filed
whose default value is auth.user.first_name, but I noticed that when I
try to run the app it gives me an error since there is no user logged
in and auth.user  == None and the None value doesnt have a first_name
attribute. How then do I solve this?
P.S: I hope my explanation is clear enough?