maximum_depth_of_n_ary_tree.py

# Definition for a Node.
class Node:
    def __init__(self, val=None, children=None):
        self.val = val
        self.children = children


class Solution:
    def maxDepth(self, root: Node) -> int:
        if root is None: return 0
        max_depth = 0
        for child in root.children:
            max_depth = max(max_depth, self.maxDepth(child))
        return 1 + max_depth