[Zope] Form action with Python script and arguments

I have two problems when I want for pass <FORM ...> information into a Python Script: 1) Besides passing the FORM data, I also need to pass an extra argument into the Python script that was passed (as <URL>?arg=argval) by the URL. A thing like: <FORM action=my_py_script(arg=<dtml-var argval>) doesn't work. Neither does: <FORM action="my_py_script(arg=<dtml-var argval>") What's the proper syntax for passing extra arguments to a Python script in a FORM action? 2) How do I access the FORM data in a Python script? I've tried "import cgi" but a call to cgi.FieldStorage() was met by a message that I wasn't authorized to make this call ... Thanks, --Henk