For a binary tree T, we can define a flip operation as follows: choose any node, and swap the left and right child subtrees.

A binary tree X is flip equivalent to a binary tree Y if and only if we can make X equal to Y after some number of flip operations.

Write a function that determines whether two binary trees are flip equivalent.  The trees are given by root nodes root1 and root2.

Example 1:

Input: 
root1 = [1,2,3,4,5,6,null,null,null,7,8], 
root2 = [1,3,2,null,6,4,5,null,null,null,null,8,7] 
Output: true 
Explanation: We flipped at nodes with values 1, 3, and 5. 

Note:

1. Each tree will have at most 100 nodes.
2. Each value in each tree will be a unique integer in the range [0, 99].

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def flipEquiv(self, root1: TreeNode, root2: TreeNode) -> bool:
        if root1 == root2 == None:
            return True
        
        elif root1 and root2 and root1.val == root2.val:
            return (self.flipEquiv(root1.left, root2.left) and self.flipEquiv(root1.right, root2.right)) or (self.flipEquiv(root1.right, root2.left) and self.flipEquiv(root1.left, root2.right))
        
        else:
            return False