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import { TreeNode } from "../binary-tree-inorder-traversal/TreeNode.ts";
export default function searchBST(    root: TreeNode | null,    val: number,): TreeNode | null | undefined {    if (!root) return null;    if (root.val > val) {        return searchBST(root.left, val);    } else if (root.val < val) return searchBST(root.right, val);    if (root.val === val) return root;    return;}