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class Solution:
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    def rangeSumBST(self, root, L, R):
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        if not root:
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            return 0
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        if L <= root.val <= R:
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            return (
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                root.val
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                + self.rangeSumBST(root.left, L, R)
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                + self.rangeSumBST(root.right, L, R)
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            )
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        elif root.val < L:
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            return self.rangeSumBST(root.right, L, R)
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        else:
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            return self.rangeSumBST(root.left, L, R)