[mod_python] How to check if session is created because of old session expired?

Hello

I was trying to find out solution for my problem but there were no
perfect answers in google so I would like to ask You.
I want to check if session is created by FileSession because of old
session expired or new user with new session.
I checked function is_new(), but it return 1 in both cases. Is there
any solution for it?
Maybe it could be good to add information in new session when old
session expired?

regards
--
Radosław Rymaszewski