合并排序的两个链表--python

#合并两个递增的链表并使新链表依旧按照递增排序--递归实现
def mergeLinkedList(pHead1, pHead2):
    if pHead1 is None:
        return pHead2
    elif pHead2 is None:
        return pHead1
    pMergeHead = None
    if pHead1.val < pHead2.val:
        pMergeHead = pHead1
        pMergeHead.next = mergeLinkedList(pHead1.next, pHead2)
    else:
        pMergeHead = pHead2
        pMergeHead.next = mergeLinkedList(pHead1, pHead2.next)
    return pMergeHead