二叉樹の鏡像[剣指offer]のpython実現

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    #          
    def swap(self , root):
        temp=root.left
        root.left=root.right
        root.right=temp

    def Mirror(self, root):
        # write code here
        if root==None:
            return root
        else:
            self.swap(root)
            self.Mirror(root.left)
            self.Mirror(root.right)
            return root