Maximum Depth of Binary Tree Python Solution

lcpy gen -n 104   # by problem number
lcpy gen -s maximum_depth_of_binary_tree   # by problem name

Input: root = [3,9,20,null,null,15,7]
Output: 3

Input: root = [1,null,2]
Output: 2

from leetcode_py import TreeNode


class Solution:
    # Time: O(n)
    # Space: O(h)
    def max_depth(self, root: TreeNode[int] | None) -> int:
        if not root:
            return 0

        left_depth = self.max_depth(root.left)
        right_depth = self.max_depth(root.right)

        return 1 + max(left_depth, right_depth)