Given a binary tree where all the right nodes are either leaf nodes with a sibling (a left node that shares the same parent node) or empty, flip it upside down and turn it into a tree where the original right nodes turned into left leaf nodes. Return the new root.

public class Solution {
    public TreeNode upsideDownBinaryTree(TreeNode root) {
        if (root == null || (root.left == null && root.right == null)) return root;

        TreeNode newRoot = upsideDownBinaryTree(root.left);
        root.left.left = root.right;
        root.left.right = root;
        root.left = null;
        root.right = null;
        return newRoot;
    }
}

class Solution:
    def upsideDownBinaryTree(self, root: TreeNode) -> TreeNode:
        if not root or not root.left:
            return root

        new_root = self.upsideDownBinaryTree(root.left)
        root.left.left = root.right
        root.left.right = root
        root.left = root.right = None
        return new_root