---

class Binary_Search_Tree:
    def append(self, val):
        new_node = Node(val)
        if not self.root:
            self.root = new_node
            return
        cur = self.root
        while cur:
            if cur.val > val:
                if not cur.left:
                    cur.left = new_node
                    return
                cur = cur.left
            else:
                if not cur.right:
                    cur.right = new_node