mitmdump加-s使用python脚本时

代码内容如下:

import json
import pymongo
from mitmproxy import ctx

client = pymongo.MongoClient('localhost')
db = client['kuaishou']
collection = db['data']


def response(flow):

    if '/rest/n/feed/hot' in flow.request.url:
        text = flow.response.text
        list = json.loads(text)['feeds']
        for i in list:
            try:
                url = i['main_mv_urls'][0]['url']
            except KeyError:
                continue
            data = {
                'describe': i['caption'],
                'url': url,
                'author': i['user_name'],
                'id': i['user_id'],
                'comments': ''
            }
            collection.insert(data)

在命令行报错，说pymongo无法找到，这该咋整，求解