TypeError: list indices must be integers or slices, not str为什么会出现这个错误啊？

import requests
url="https://dushu.baidu.com/api/pc/getCatalog?data={'book_id':'4306063500'}"
resp=requests.get(url)
dic=resp.json()

for item in dic['data']['novel']['items']:
title=item ['title']
cid =item['cid']
print(cid)

提示列表的下标必须为整形数字或者slices对象，打印一下看看dic吧