def _items(self, req, server_id, entity_maker):
        """Returns a list of VIFs, transformed through entity_maker."""
        context = req.environ['nova.context']
        instance = common.get_instance(self.compute_api, context, server_id)

        try:
            vifs = self.network_api.get_vifs_by_instance(context, instance)
        except __HOLE__:
            msg = _('Listing virtual interfaces is not supported by this '
                    'cloud.')
            raise webob.exc.HTTPBadRequest(explanation=msg)
        limited_list = common.limited(vifs, req)
        res = [entity_maker(vif) for vif in limited_list]
        return {'virtual_interfaces': res}
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/api/openstack/compute/legacy_v2/contrib/virtual_interfaces.py/ServerVirtualInterfaceController._items