equivalent of source <file> in python?

[Astan Chee]

Hi,
I'm trying to convert my tcsh script to python and am stuck at one part, 
particularly the part of the script that looks like this:

#!/bin/tcsh
setenv LSFLOG /var/tmp/lsf_log
source /etc/setup
unalias cp
umask 0
env >> ${AFLOG}

What is the equivalent of doing this in python2.5?
Thanks again