[Zope] Picking up a parameter in a ZPT

I'm trying to work out how to pass parameters between various modules running under Zope and have got stuck. In the line below, I need to replace the word 'links' with a variable passed by the calling program python:here.parse_file(file=context.links,sepr=',',clone=1)"> I know I can pass the variable using:- <dtml-var expr="test2(parm='links')"> Just don't know how to reference it under ZPT. Help! -- John