Problem - Search in BST

Given the root of a BST and an integer val, find the node with that value and return the subtree rooted at that node. If the node doesn't exist, return null.

Example: In BST $[4,2,7,1,3]$, searching for 2 returns subtree $[2,1,3]$. You're implementing the most basic BST operation.

Use the BST property to decide which direction to search. Constraints: up to $5000$ nodes, values from $1$ to $10^7$.