python code

```
class Solution(object):
def threeSum(self, nums):
"""
:type nums: List[int]
:rtype: List[List[int]]
"""
return self.helper(sorted(nums), [])
def helper(self, nums, lst):
if (len(lst) == 3):
if (sum(lst) == 0):
return [lst]
else:
return []
elif (len(nums) == 0):
return []
else:
withElem = self.helper(nums[1:], lst + [nums[0]]);
withoutElem = self.helper(nums[1:], lst);
return withElem + withoutElem
```

output is [[-1,-1,2],[-1,0,1],[-1,0,1]], 35ms

my problem is how to make ouput distinct