[Zope] renaming large list of objects

[alan runyan]

have a bunhca files that dont have extensions.. I know 
their extensions should be .abc so I'm trying to append 
this to their names... with no success :( :

all 'Files' needing to be renamed to original_id + '.abc'

<dtml-in "PARENTS[0].objectValues(['File'])">
   <dtml-call "REQUEST.set('new_name', _.string.join(_
['id'], '.abc') )">
  <dtml-call "manage_renameObject(id, new_name ,REQUEST)">
</dtml-in>

some problems I'm having is in the _.string.join
('original', '_name') suppose returns original_name but 
when I do the _['id'] it returns o r i g i n a l (many 
seperate objects)

acks: my python skills are low
Zope 2.1.4 install