def importHelper(self, struct):
        m = StrStrHashMap()
        keysAndValues = struct.get(self.__field)
        for i in range(0, len(keysAndValues), 2):
            m[keysAndValues[i]] = keysAndValues[i+1]
        return m
def dfs(self,candidates,target,start,reslist):
        length = len(candidates)
        if target == 0: 
            return self.result.append(reslist)