[Zope] ZCatalog of method output

I read you could define a ZClass instance's method as a field-index of a ZCatalog; but it's not working for me. The DTML method dept_code is simply: <dtml-return "_.string.split(jobcode,'-')[0]"> When I call the method directly it returns a single character, the first character of the jobcode. The method dept_code is defined as a field-index of the ZCatalog JobsCat. But when I access JobsCat thus: <dtml-in "JobsCat(meta_type='Job Opening', sort_on='dept_code')"> <li> <a href="<dtml-var "JobsCat.getpath(data_record_id_)">"> (<dtml-var dept_code>) <dtml-var jobcode>: <dtml-var title></a> </dtml-in> the items are not sorted, and dept_code is null. Can anyone see what I'm doing wrong? -- Thanks -- Loren