def tearDown(self):
        super(SimpleInstanceTest, self).tearDown()
        CONF.network_label_regex = self.orig_conf
        CONF.ip_start = None
def myfunc(first, second=None, third=Optional(5), fourth=Optional(execute=list)):
            #Equivalent: second = deoption(second, 5)
            if isinstance(second, type(None)):
                second = 5