human
Give me a the Python program you requested given the following:
I found an interesting problem on https://leetcode.com/problems/sort-list/:
Sort a linked list in O(n log n) time using constant space complexity.

Example 1:

Input: 4->2->1->3
Output: 1->2->3->4

Example 2:

Input: -1->5->3->4->0
Output: -1->0->3->4->5

I tried it in Python, but could not do it. Can you solve it?
assistant
#Here is the Python program you requested.

# Definition for singly-linked list.
 # class ListNode:
 #     def __init__(self, x):
 #         self.val = x
 #         self.next = None
 
 class Solution:
     def sortList(self, head):
         l = []
         traverse, traverse2 = head, head
         while(traverse) != None:
             l.append(traverse.val)
             traverse = traverse.next
         l.sort()
         for num in l:
             traverse2.val = num
             traverse2 = traverse2.next
         return head