def deleteDuplicates(self, head):
        cur = head
        while cur:
            runner = cur.next
            while runner and runner.val == cur.val:
                runner = runner.next
            cur.next = runner
            cur = runner
        return head
:type head: ListNode
dataset/ETHPy150Open kamyu104/LeetCode/Python/remove-duplicates-from-sorted-list.py/Solution.deleteDuplicates