[Zope] catching exceptions in zpt

[David Bear]

I'm trying to do something like this in a zpt

<meta tal:define="global target python:here.mysript(request.target) | 
nothing" />

however, if my request did not have ?target=blah I get an attributeError 
because of course the request has not parameter called target. I assumed that 
the pipe 'or nothing' would handle an equivalent except AttributeError block 
but it doesnt.

how can I put in my zpt a way to catch if request has no attribute?

-- 

David Bear
College of Public Programs/ASU
411 N Central, Phoenix, AZ 85004