[Zope] Python script returning link to local file

Hi, I want to use a Python script for returning a link to a local file (in a LocalFS object) in ZPT. The parameter given is the id of the file and is named file. from AccessControl import getSecurityManager user = getSecurityManager().getUser() username = user.getUserName() return container[username].[file] This doesn't work. Is it a reference problem ? Regards, Michael