'Returns a list of volumes, transformed through entity_maker.'

def _items(self, req, entity_maker):

    context = req.environ['nova.context']
    context.can(vol_policies.BASE_POLICY_NAME)
    volumes = self.volume_api.get_all(context)
    limited_list = common.limited(volumes, req)
    res = [entity_maker(context, vol) for vol in limited_list]
    return {'volumes': res}
