Hi, here's your problem today. This problem was recently asked by Microsoft:

Given a binary tree, find the level in the tree where the sum of all nodes on that level is the greatest.

Here's an example and some starter code.

```
class Node:
def __init__(self, value, left=None, right=None):
self.value = value
self.left = left
self.right = right
def __repr__(self):
return f"(Value: {self.value} Left: {self.left} Right: {self.right})"
def tree_level_max_sum(root):
# Fill this in.
n3 = Node(4, Node(3), Node(2))
n2 = Node(5, Node(4), Node(-1))
n1 = Node(1, n2, n3)
"""
1 Level 0 - Sum: 1
/ \
4 5 Level 1 - Sum: 9
/ \ / \
3 2 4 -1 Level 2 - Sum: 8
"""
print(tree_level_max_sum(n1))
# Should print 1 as level 1 has the highest level sum
```