如何在二叉搜索树中获得给定值的高度(当给定值为字符串时)

class Node:
    def __init__(self, value):
        self.value = value
        self.left = None
        self.right = None

def insert(root, value):
    if root is None:
        return Node(value)
    if value < root.value:
        root.left = insert(root.left, value)
    else:
        root.right = insert(root.right, value)
    return root

def getHeight(root, target):
    if root is None:
        return 0
    if root.value == target:
        return 1
    if target < root.value:
        return getHeight(root.left, target) + 1
    else:
        return getHeight(root.right, target) + 1

# 创建二叉搜索树
root = None
root = insert(root, 5)
root = insert(root, 3)
root = insert(root, 7)
root = insert(root, 2)
root = insert(root, 4)
root = insert(root, 6)
root = insert(root, 8)

# 获取给定值的高度
target = "4"
height = getHeight(root, target)
print("给定值 {} 在二叉搜索树中的高度为 {}".format(target, height))