[Zope] Calling a sequence-item functions

[Wim Bekker]

I would like to call a python function from a sequence item:

<dtml-in "Catalog(page_type='issuedtml')" prefix="x">
1: <dtml-var expr="x_item.title">
2: <dtml-var expr="x_item.GetTitle()">
3: <dtml-var expr="x_item.GetObjectTitle(x_item)">

in class TrackerSupport I have:

def GetTitle(self)
	return self.title

def GetObjectTitle(self,object)
	return object.title


1: gives the correct title
2: gives the title from the page where the dtml code is in.
3: gives the correct title.

Why is GetTitle not working?
Where can I find some info on this subject?

Wim