python实现合并两个有序链表

 def merge_list(self, l1, l2):
        if l1 and l2:
            p1, p2 = l1, l2
            fakeHead = ListNode(None)
            cur = fakeHead
            while p1 and p2:
                if p1.val <= p2.val:
                    cur.next = p1
                    p1 = p1.next
                else:
                    cur.next = p2
                    p2 = p2.next
                cur = cur.next
            cur.next = p1 if p1 else  p2
            return fakeHead.next
        return l1 or l2