**Solution**

**Nested List Weight Sum** https://leetcode.com/problems/nested-list-weight-sum/

- We use a simple DFS to compute the nested list weight.The outermost list has level 1.
- Beyond that we just need to loop across all items in the nested list. If item is an integer, update the weighted sum. Otherwise make a recursive call with the nested list and updated level.

```
class Solution(object):
def depthSum(self, nestedList):
"""
:type nestedList: List[NestedInteger]
:rtype: int
"""
self.d_sum = 0
self.helper(nestedList, 1)
return self.d_sum
def helper(self, nestedList, level):
for x in nestedList:
if x.isInteger():
self.d_sum = self.d_sum + x.getInteger()*level
else:
self.helper(x.getList(), level+1)
return
```