[Zope] What is the Python script that is similar to a dtml-in call

Hi, I need some advice. I still use dtml calls in my systems. My problem is if the user is searching for a record but the record is not found. The call is as follows: <dtml-call "REQUEST.set('serial_number', serial_number)"> <dtml-in lookup_header_record> <dtml-call "REQUEST.set('equip_type', equip_type)"> <dtml-call "REQUEST.set('pr', pr)"> </dtml-in> If the record is not found I get this error: Error Type: KeyError Error Value: equip_type True statement since there is not record and further in the form I am trying to output this variable. Are there any examples that either traps for an error or python script that can also lookup the record and true a found/not found status. Thanks, Larry