1def sum_numbers(root):
2 def dfs(node, curr_num):
3 if not node:
4 return 0
5 curr_num = curr_num * 10 + node.val
6 if not node.left and not node.right:
7 return curr_num
8 return dfs(node.left, curr_num) + dfs(node.right, curr_num)
9
10 return dfs(root, 0)