559. Maximum Depth of N-ary Tree - LeetCode Solution

class Solution:
    def maxDepth(self, root: 'Node') -> int:
                

        if not root: 
            return 0
        
        def f(root):
            if not root.children: return 1
            h = -1
            for v in root.children:
                h = max(h, f(v))
            return 1 + h
        return f(root)