new_contents: """Leetcode 938. Range Sum of BST
  Easy
  
  URL: https://leetcode.com/problems/range-sum-of-bst/
  
  Given the root node of a binary search tree, return the sum of values of all
  nodes with value between L and R (inclusive).
  
  The binary search tree is guaranteed to have unique values.
  
  Example 1:
  Input: root = [10,5,15,3,7,null,18], L = 7, R = 15
  Output: 32
  
  Example 2:
  Input: root = [10,5,15,3,7,13,18,1,null,6], L = 6, R = 10
  Output: 23
  
  Note:
  - The number of nodes in the tree is at most 10000.
  - The final answer is guaranteed to be less than 2^31.
  """
  
  # Definition for a binary tree node.
  class TreeNode(object):
      def __init__(self, val):
          self.val = val
          self.left = None
          self.right = None
  
  
  class Solution(object):
      def rangeSumBST(self, root, L, R):
          """
          :type root: TreeNode
          :type L: int
          :type R: int
          :rtype: int
          """
          pass
  
  
  def main():
      pass
  
  
  if __name__ == '__main__':
      main()
  
subject: Add lc0938_range_sum_of_bst.py