python xpath request json

import requests
from lxml import etree
import json
header_data={
    "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/100.0.4896.127 Safari/537.36"
}
resp=requests.get(url,headers=header_data)
resp.encoding='utf-8'
time_list='/html/body/div[4]/div/div[1]/div[2]/div[1]/ul/li/span/text()'
title_list='/html/body/div[4]/div/div[1]/div[2]/div[1]/ul/li/a/text()'
text_content=resp.text
tree=etree.HTML(text_content)
titles=tree.xpath(title_list)
str='{}'
a=json.dumps(str,ensure_ascii=False)