[Zope] entering a folder

How do I go into a folder rather than just call it, ie. the equivalent of cd folderName in DOS I tried, as part of a dtml-in loop: <dtml-call "absolute_url() + '/'+_['sequence-item']"> this calls the folder but does not go into it I want to go into it so that I can set a local role <dtml-call expr="manage_addLocalRoles(_['sequence-item'],['Manager'])"> this line works but is setting the local roles in the parent folder, I want them set in the child folders then I want to back out of it, the equivalent to cd.. I looked in Appendix B under Folder, get, manage but no joy I tried "this(absolute_url() + '/'+_['sequence-item']" and "this('absolute_url() + '/'+_['sequence-item']' "but didn't work - Bill Kerr