爬去网页时出现raise etree.ParserError(lxml.etree.ParserError: Document is empty问题，想知道哪里出现了错误源代码如下

import requests

from urllib import response

import lxml.html

import csv

from requests import Response

doubanurl = 'https://movie.douban.com/top250?start={}&filter='

def getSource(url):

    #获取目标网页
    response = requests.get(url)
    response.encoding = 'utf-8'
    return response.content

def getEveryItem(source):

    selector = lxml.html.document_fromstring(source)

    movieItemList = selector.xpath('//div[@class="info"]')

    movieList = []

    for eachMovie in movieList:

        movieDict = {}
        title = eachMovie.xpath('div[@class="hd"]/a/span[@class="title"]/text()')
        print(title)
        otherTitle = eachMovie.xpath('div[@class="hd"]/a/span[@class="other"]/text()')
        link = eachMovie.xpath('div[@class="hd"]/a/@href')[0]
        star = eachMovie