Symmetric Tree

main.py

class Solution:
    def isSymmetric(self, root: TreeNode) -> bool:
        return self.isMirror(root, root)
    
    def isMirror(self, left_node: TreeNode, right_node: TreeNode) -> bool:
        if not left_node and not right_node:
            return True
        if (not left_node) or (not right_node):
            return False
        if left_node.val != right_node.val:
            return False
        return self.isMirror(
            left_node.left, right_node.right) and self.isMirror(
                left_node.right, right_node.left)