检查给定值是否在二进制搜索树中

Question

这是我得到的代码，我需要对其进行更改。该函数在给定的BST中查找值，如果target在树中，则返回True。代码如下：

def member_prim(tnode, target):
    """
    Purpose:
        Check if target is stored in the binary search tree.
    Pre-Conditions:
        :param tnode: a treenode with the BST property
        :param target: a value
    Post-Conditions:
        none
    Return
        :return: True if target is in the tree
    """

    if tnode is None:
        return False
    elif target < tnode.data:
        right = tnode.right
        return member_prim(right, target)
    else:
        tnode.right = tnode.left
        return member_prim(tnode.right, target)

我对代码做了一些修改，下面是我所做的：

if tnode is None:
    return False
elif tnode.data is not target:
    return False
elif target > tnode.data:
    right = tnode.right
    return member_prim(right, target)
else:
    tnode.right = tnode.left
    return member_prim(tnode.right, target)

它仍然抛出属性错误，说对象'treenode‘没有属性'data’。

下面是treenode类：

class treenode(object):

    def __init__(self, data, left=None, right=None):
        """
        Purpose:
            Create a new treenode for the given data.
        Pre-conditions:
            data:  Any data value to be stored in the treenode
            left, right:  Another treenode (or None, by default)
        Post-condition:
            none
        """
        self.data = data
        self.left = left
        self.right = right

请让我知道我哪里出错了，以及我如何才能修复它。

Answer 1

class treenode(object):

def __init__(self, data, left=None, right=None):
    """
    Purpose:
        Create a new treenode for the given data.
    Pre-conditions:
        data:  Any data value to be stored in the treenode
        left, right:  Another treenode (or None, by default)
    Post-condition:
        none
    """
    self.data = data
    self.left = left
    self.right = right

def trav(root, target):
    if not root:
        return False
    if root.data == target:
        return True
    if root.data > target:
        return trav(root.left, target)
    if root.data < target:
        return trav(root.right, target)

这段代码会告诉你目标值是否存在。