[mod_python] Cookie problem

Hi,
I create a cookie and set it to expire in 2 weeks like this:

 cookie = Cookie.Cookie('foo', bar)
 cookie.expires = time() + 1209600  # 2 weeks
 Cookie.add_cookie(req, cookie)

But whatever I set "expires" to it is always set to "end of session".
I also tried doing this: Cookie.add_cookie(req, 'foo', bar, expires=time() +
1209600)

but that doesn't change anything. Is this because I use sessions too?