[Zope] Testing a value returned from a Zope Python Script

Hello. I am trying to test a value returned from a Python script using the following syntax: <dtml-if expr="<dtml-call expr="checkRowLength(fileObject_index, rowLength)"> == 0"> </dtml-if> checkRowLength is the name of the script. Apparently Zope flags me with an error saying that this is an invalid attribute tag for a dtml-if. Is there any other way of achieving this? Any help would be appreciated. -Asad __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com