Leetcode 100 Same Tree python

题目：

Given two binary trees, write a function to check if they are equal or not.

Two binary trees are considered equal if they are structurally identical and the nodes have the same value.

 class Solution(object):
     def isSameTree(self, p, q):
         if p == None and q == None:
             return True
         elif p == None and q != None:
             return False
         elif p != None and q == None:
             return False
         elif p.val != q.val:
             return False
         elif p.val == q.val:
             return self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)