def test_filter_ips_white_list(self):
        CONF.network_label_regex = '.*'
        CONF.ip_regex = '^(15.|123.)'
        CONF.black_list_regex = '^10.123.123.*'
        ip = self.instance.get_visible_ip_addresses()
        ip = filter_ips(
            ip, CONF.ip_regex, CONF.black_list_regex)
        self.assertEqual(2, len(ip))
        self.assertTrue('123.123.123.123' in ip)
        self.assertTrue('15.123.123.123' in ip)
def addOperators(self, num, target):
        """
        Adapted from https://leetcode.com/discuss/58614/java-standard-backtrace-ac-solutoin-short-and-clear

        Algorithm:
        1. DFS
        2. Special handling for multiplication
        3. Detect invalid number with leading 0's
        :type num: str
        :type target: int
        :rtype: List[str]
        """
        ret = []
        self.dfs(num, target, 0, "", 0, 0, ret)
        return ret