1302. Deepest Leaves Sum - LeetCode

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution:

    def dfs(self, node: TreeNode, deepness):
        if node.left != None:
            self.dfs(node.left, deepness+1)
        if node.right != None:
            self.dfs(node.right, deepness+1)
        if (node.left is None) and (node.right is None):
            if deepness == self.deepest:
                self.sum += node.val
            elif deepness > self.deepest:
                self.deepest = deepness
                self.sum = node.val
            return

    def deepestLeavesSum(self, root: TreeNode) -> int:
        self.sum = 0
        self.deepest = 0
        self.dfs(root, 0)
        return self.sum