class Solution(object):
def symtr(self,root1, root2):
if(root1==None and root2==None):
return True
elif(root1==None and root2!=None or root1!=None and root2==None or root1.val != root2.val):
return False
return symtr(root1.right,root2.left) and symtr(root1.left,root2.right)
def isSymmetric(self, root):
if(root==None):
return True
else:
x=symtr(root.left,root.right)
return x