leetcode- same tree problem

sametree.py

'''
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.
'''
# Definition for a  binary tree node
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    # @param p, a tree node
    # @param q, a tree node
    # @return a boolean
    def isSameTree(self, p, q):
        if p is None and q is None:
            return True
        if p is None and q is not None:
            return False
        elif p is not None and q is None:
            return False
            
        if p.val != q.val:
            return False
        else:
            if self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right):
                return True
            else:
                return False