Python beat 90% simple solution
\nclass Solution:\n    def rangeSumBST(self, root: TreeNode, L: int, R: int) -> int:\n        if not root:\n            return 0\n        elif root.val >= L and
```\nclass Solution:\n    def rangeSumBST(self, root: TreeNode, L: int, R: int) -> int:\n        if not root:\n            return 0\n        elif root.val >= L and root.val <= R:\n            return root.val + self.rangeSumBST(root.left, L, R) + self.rangeSumBST(root.right, L, R)\n        elif root.val < L:\n            return self.rangeSumBST(root.right, L, R)\n        else:\n            return self.rangeSumBST(root.left, L, R)\n```
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