human
I found an interesting problem on https://leetcode.com/problems/kth-smallest-element-in-a-bst/:
Given a binary search tree, write a function kthSmallest to find the kth smallest element in it.

Note: 
You may assume k is always valid, 1 ≤ k ≤ BST's total elements.

Example 1:

Input: root = [3,1,4,null,2], k = 1
   3
  / \
 1   4
  \
   2
Output: 1

Example 2:

Input: root = [5,3,6,2,4,null,null,1], k = 3
       5
      / \
     3   6
    / \
   2   4
  /
 1
Output: 3

Follow up:
What if the BST is modified (insert/delete operations) often and you need to find the kth smallest frequently? How would you optimize the kthSmallest routine?

I tried it in Python, but could not do it. Can you solve it?
assistant
#Here is Python code to find the kth smallest element in it.

# Definition for a binary tree node.
 # class TreeNode:
 #     def __init__(self, x):
 #         self.val = x
 #         self.left = None
 #         self.right = None
 
 class Solution:
     def kthSmallest(self, root, k):
         """
         :type root: TreeNode
         :type k: int
         :rtype: int
         """
         count=[0]
         ans=[None]
         
         def search (head):
             if not head:
                 return
             if head.left:
                 search(head.left)
             count[0] +=1
             print(k,count[0])
             if count[0]==k:
                 ans[0]=head.val
             search(head.right)
         search(root)
         return ans[0]