[Zope] Accesing a new context from a manipulated string

[Michael Bernstein]

Here's my problem:

given a method itemURL(), that typically returns a site
relative URL such as '/about/', I need to change to the
appropriate directories context using <dtml-with>.

In short I need to do the equivalent of <dtml-with about>.

The closest I've gotten so far is:

<dtml-with expr="_.getitem(itemURL(), 0)">

which generates a KeyError: /about/ in the traceback.

Can anyone help me truncate the extra '/'s off of this
string and pass it to the <dtml-with>?

Michael Bernstein.