[Zope] External Python Script

Hello All, My ZPT is just starting to be passable and I have a working database :-) What I would like is a quick overview of how to make an external python script run from Zope. Just the concept so I can go figure the details... I have a script /projects/htl/printlabel.py which takes 4 parameters (currently from the command line) and sends some text to lpr which prints my label. Do I need to make a python script or a product or what? TIA Simon