Insertion sort python solution
class Solution(object):\n        def insertionSortList(self, head):\n            if not head or not head.next:\n                return head\n    \n            d
    class Solution(object):\n        def insertionSortList(self, head):\n            if not head or not head.next:\n                return head\n    \n            dummy = ListNode(None)\n            dummy.next, tail = head, head.next\n            dummy.next.next = None\n    \n            while tail:\n                pre, current, next = dummy, dummy.next, tail.next\n                while current:\n                    if tail.val <= current.val:\n                        pre.next, tail.next = tail, current\n                        break\n                    pre, current = current, current.next\n                else:\n                    pre.next, tail.next = tail, None\n                tail = next\n    \n            return dummy.next
['Python']