[Zope] Debugging a python routine

Can anyone suggest how I would go about debugging a Python routine like this through Zope? <span tal:define="opts python:here.lib.parse_file(file=here.members,sepr=',',clone=1)"> <tal:block repeat="opt opts"> <li><a tal:content="python:opt[1]" tal:attributes="href python:opt[0]"></a></li> </tal:block> </span> -- John