def tearDown(self):
        super(SimpleInstanceTest, self).tearDown()
        CONF.network_label_regex = self.orig_conf
        CONF.ip_start = None
def json_usage(root):
    root = os.path.abspath(root)
    result = [['Path', 'Parent', 'Usage']]
    result.extend(entry for entry in usage_iter(root))
    return json.dumps(result)