Leetcode (Python): Path Sum II

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.
For example:
Given the below binary tree and sum = 22,

              5
             / \
            4   8
           /   / \
          11  13  4
         /  \    / \
        7    2  5   1

return

[
   [5,4,11,2],
   [5,8,4,5]
] 

Solution:

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

class Solution:
    # @param root, a tree node
    # @param sum, an integer
    # @return a list of lists of integers
    def pathSum(self, root, sum):
        solution = []
        self.pathSumRec(root, sum, 0, [], solution)
        return solution
    
    def pathSumRec(self, root, sum, tempSum, tempList, solution):
        if root == None:
            return
        tempList.append(root.val)
        tempSum += root.val
        if root.left == None and root.right == None:
            if tempSum == sum:
                solution.append(list(tempList))
        else:
            self.pathSumRec(root.left, sum, tempSum, tempList, solution)
            self.pathSumRec(root.right, sum, tempSum, tempList, solution)
        tempList.pop()