[Zope] Help on syntax (please!)

Hello, can someone please explain to me (a Zope newby) why this fragment avaluates always to the KO branch ? <dtml-in get_valid_userids prefix="seq"> <dtml-if "seq_item == AUTHENTICATED_USER "> OK <dtml-else> KO item: <dtml-var AUTHENTICATED_USER><br> user: <dtml-var seq_item><br> </dtml-if> </dtml-in> thanks in advance !! peppo