Write a function that takes in a ...

Write a function that takes in a potentially invalid Binary Search Tree (BST) and returns a boolean representing whether the BST is valid. Each BST node has an integer value, a left child node, and a right child node. A node is said to be a valid BST node if and only if it satisfies the BST property: its value is strictly greater than the values of every node to its left; its value is less than or equal to the values of every node to its right; and its children nodes are either valid BST nodes themselves or None/Null. A BST is valid if and only if all of its nodes are valid BST nodes. Sample Input: tree = 10 / \ 5 15 / \ / \ / \ / \ 2 5 13 22 / \ 1 14 Sample Output: true