[mod_python] How to define an environment variable for other python module to use?

I have other python modules which usually need to read some environment
variables, e.g., an python-oracle interface module needs to read the "ORACLE_SID"
to know where the database to connect. I used to defining this variable in the "shell"
before invoking a python CGI program, e.g.:

   #!/bin/sh
   export ORACLE_SID=orcl
   exec /some/oracle/python/interface.cgi

I would like to try the mod_python using the default CGI handler, but does someone
know how to define some environment variable in mod_python?

Thanks

david