Python使用xpath无论如何都返回空列表

Question

#爬取58二手房中的房源信息
import requests
from lxml import etree
import lxml
url='https://bj.58.com/ershoufang/'
headers={
    'User-Agent':'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.80 Safari/537.36 Edg/98.0.1108.50'
}
resp=requests.get(url=url,headers=headers)
resp.encoding='utf-8'
page_text=resp.text
with open('./text','w',encoding='utf-8') as fp:
    fp.write(page_text)
#数据解析
tree=etree.HTML('page_text')
print(tree)
#存储的就是div标签对象
div_list=tree.xpath('//head')
print(div_list)

结果：第一个tree没问题，但无论在xpath后面放什么都返回空列表

Answer 1

tree=etree.HTML('page_text')
改为
tree=etree.HTML(page_text)

加载变量的值，而不是直接加载page_text这字符，当然无法找到内容