[mod_python] cache-control and session-id

If I use sessions, mod_python adds a header

< Cache Control no-cache="Set Cookie">

What I can't make out despite searching all over google is whether by 
default the page generated will get cached by proxies if I don't include 
a cache-control header.

I must admit I thought that without any cache-control header, proxies 
would not cache the page.

I assume that the no-cache option means the session cookie is not 
cached. That is my understanding of the info I have read.

I'm not that clued up on caching, so I'm hoping that someone can give me 
the real facts if any on this

Hoping for some enlightenment.

Regards

John Aherne