[Zope] string find

Hi, How can I find a string in a dtml-var inside a <dtml-in> sequence? I only want to show names including 'fam'. I don't want to use the ZCatalog for this search! I want to know how I can perform a string compair. <dtml-in Catalog> <dtml-if "_.string.find('fam',<dtml-var name>"> this is not correct, why? <dtml-var name> </dtml-if> </dtml-in> thanks for help mex