[Zope-CMF] Finding a username by local role

[Lars H. Korte]

Hi,
how is it possible (in a python script) to find the username of a
person, who has a certain local role in a special context?

I've triedthe following:
myRole = context.portal_membership.users_with_local_role('Leiter')
This returns an empty list

..and this
yourRole = context.portal_membership.users_with_local_role('Owner')
.. always returns the superuser, ignoring other users that have the
"owner"-role in a context.
Shouldn't that return a list of people?

I would appreciate your help

regards
Lars