range sum of bst

 1# Definition for a binary tree node.
 2# class TreeNode:
 3#     def __init__(self, val=0, left=None, right=None):
 4#         self.val = val
 5#         self.left = left
 6#         self.right = right
 7class Solution:
 8    def rangeSumBST(self, root: TreeNode, L: int, R: int) -> int:
 9        def rec(node):
10            if node.left:
11                rec(node.left)
12            if node.right:
13                rec(node.right)
14            total[0] += node.val if L <= node.val <= R else 0
15        total = [0]
16        rec(root)
17        return total[0]