当使用顺序遍历访问所有节点时，为什么镜像树不起作用？

    1
   / \
  2   3
 / \ / \
4  5 6  7

    1
   / \
  3   2
 / \ / \
7  6 5  4

class TreeNode:
    def __init__(self, value=0, left=None, right=None):
        self.value = value
        self.left = left
        self.right = right

def pre_order_traversal(root):
    if root:
        print(root.value, end=' ')
        pre_order_traversal(root.left)
        pre_order_traversal(root.right)

# 创建原树
original_tree = TreeNode(1, TreeNode(2, TreeNode(4), TreeNode(5)), TreeNode(3, TreeNode(6), TreeNode(7)))

# 镜像化树
def mirror_tree(root):
    if root:
        root.left, root.right = root.right, root.left
        mirror_tree(root.left)
        mirror_tree(root.right)

# 镜像化原树
mirrored_tree = original_tree
mirror_tree(mirrored_tree)

# 在镜像树上进行前序遍历
print("镜像树的前序遍历结果：")
pre_order_traversal(mirrored_tree)