Symmetric Tree (Leetcode 101)

Problem Link: https://leetcode.com/problems/symmetric-tree/

class Solution:
   
    def isSymmetric(self, root: Optional[TreeNode]) -> bool:

        lroot=root.left
        rroot=root.right
        
        def fun(lroot,rroot):
            
            if(lroot is None and rroot is None):
                return True
            if(lroot is None or rroot is None):
                return False
            
            f=fun(lroot.left,rroot.right)
            s=fun(lroot.right,rroot.left)
            if(lroot.val==rroot.val and f and s):
                return True
            return False
        
        return fun(lroot,rroot)