def unicode_test(seg_instance, seg_str):
            seg_gen_str = str(seg_instance)

            self.assertEqual(len(seg_gen_str), 240)
            self.assertEqual(len(seg_str), 240)
            self.assertEqual(seg_gen_str, seg_str)
def combinationSum(self, candidates, target):
        candidates.sort()
        self.result = []
        self.dfs(candidates,target,0,[])
        return self.result