[Zope] tree tag example fails

[jon@totient.demon.co.uk]

This example here :-
http://www.zope.org/Members/anthony/tree-coding-tricks

with the external method

class _dummy:
    def __init__(self, name):
        self.name=name

def child_lookup(parent):
    c = []
    for i in range(0,5):
        c.append(_dummy("%s.%d"%(parent, i)))
     return c


and dtml method

<dtml-let name="0">                        
<dtml-tree id=name branches_expr="child_lookup(parent=name)">
<b><dtml-var name></b>
</dtml-tree>
</dtml-let>


appears not to work on zope 2.2.0 or 2.1.6 on RH 6.2 with netscape
4.7x, python 1.5.2

Every node gets the label "0" and then stops expanding.

I also tried a simple example starting with a root of 1 and
computing leaves of 2x and 2x+1 but that also fails.


Any ideas what is goind on? 


Jon