TypeError: __init__() got an unexpected keyword argument 'callback'

Question

谁能告诉我出了什么错？
代码如下：

from tornado.httpclient import AsyncHTTPClient
import os
from tornado.ioloop import IOLoop

# 异步客户端
def parse(content):
    import bs4
    bs = bs4.BeautifulSoup(content,'html.parser')
    h4list = [h4.text for h4 in bs.select('ul.foot_nav.main h4')]
    for h in h4list:
        print(h)

def handle_response(response):
    body = response.body


    file = os.path.join(os.getcwd(),'templates','index.html')

    with open(file,'wb') as fw:
        fw.write(body)

    parse(body)




def load1(url,callback):
    http_client = AsyncHTTPClient()
    http_client.fetch(url,callback=callback)


load1(url='http://www.bjsxt.com',callback=handle_response)


IOLoop.instance().start()

报以下错误：

Traceback (most recent call last):
  File "E:/软件下载/Python/untitled/2020.8.13/tornado/test2/test2.py", line 32, in <module>
    load1(url='http://www.bjsxt.com',callback=handle_response)
  File "E:/软件下载/Python/untitled/2020.8.13/tornado/test2/test2.py", line 29, in load1
    http_client.fetch(url,callback=callback)
  File "C:\Users\lenovo\AppData\Local\Programs\Python\Python37\lib\site-packages\tornado\httpclient.py", line 284, in fetch
    request = HTTPRequest(url=request, **kwargs)
TypeError: __init__() got an unexpected keyword argument 'callback'

Answer 1

检查下安装的tornado版本，fetch方法说明有这么一段，从6.0开始已经移除了callback

  .. versionchanged:: 6.0

           The ``callback`` argument was removed. Use the returned
           `.Future` instead.

           The ``raise_error=False`` argument only affects the
           `HTTPError` raised when a non-200 response code is used,
           instead of suppressing all errors.
        """

所以得像这样使用

    http_client = AsyncHTTPClient()
    future= http_client.fetch(url)

    future.add_done_callback(handle_response)

https://www.tornadoweb.org/en/stable/httpclient.html