Comment 1 for bug 619106

I noticed since that I can do this with:
{{{
            subs_uri = lookup_service_root(settings.LP_SERVICE) + (
                "{version}/~{owner_name}/+archive/{ppa_name}/"
                "+subscriptions/{subscriber_name}".format(
                    version=settings.LP_VERSION, owner_name=owner_name,
                    ppa_name=ppa_name,
                    subscriber_name=subscriber_name)
            lp_subscription = self.launchpad_service.load(subs_uri)

            lp_subscription.status = 'Cancelled'
            lp_subscription.lp_save()
}}}

although of course it would be nice to not have to rely on the uri structure.