def setUp(self):
        itau_data = get_itau_data_from_file()
        self.header_arquivo = itau_data['header_arquivo']
        self.seg_p = itau_data['seg_p1']
        self.seg_p_str = itau_data['seg_p1_str']
        self.seg_q = itau_data['seg_q1']
        self.seg_q_str = itau_data['seg_q1_str']
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