python下载文件响应header里的'Content-Disposition'的filename为乱码

[孜孜求良师]

用python3.6.5的requests库请求一个下载文件，下载后文件名含中文，在谷歌上下，文件名是正常的，响应头里filename也是中文，可是用python，响应头的filename是乱码，求解，以下是源码：
# -*- coding: utf-8 -*-

import requests

url='http://gokifu.com/f/2u4y-围棋gokifu棋谱-20180425-江维杰九段-孙腾宇七段.sgf'
#定义请求头
headers=\
{
'Accept': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8',
'Accept-Encoding': 'gzip, deflate',
'Accept-Language': 'zh-CN,zh;q=0.9',
'Connection': 'keep-alive',
'Cookie': 'sc_is_visitor_unique=rx5659732.1525391933.AC91E1FBEDE74F582788C5C99288C700.11.10.9.8.6.2.2.2.1',
'Referer': 'http://gokifu.com/',
'Upgrade-Insecure-Requests': '1',
'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36'
}

response = requests.get(url,timeout=1000,headers=headers)
content=response.content.decode(encoding='utf-8')# 获取响应报文
print(content)
responseHeaders=response.headers#获取响应头
print(headers)
a = responseHeaders.get('Content-Disposition')
fileName = a[a.find('=') + 1:]#获取filename的值
print(fileName)
filename = fileName.encode().decode('utf-8')#获取响应头的解码内容
print(filename)

[oyljerry]

In [2]: res = requests.get('http://gokifu.com/f/2u4y-围棋gokifu棋谱-20180425-江维杰九段-孙腾宇七段.sgf')

In [3]: res.headers
Out[3]: {'Server': 'nginx', 'Date': 'Tue, 08 May 2018 02:54:42 GMT', 'Content-Type': 'application/x-go-sgf', 'Content-Length': '1889', 'Connection': 'keep-alive', 'Content-Description': 'File Transfer', 'Content-Disposition': 'attachment; filename=2u4y-gokifu-20180425-Sun_Tengyu-Jiang_Weijie.sgf', 'Content-Transfer-Encoding': 'binary', 'Expires': '0', 'Cache-Control': 'must-revalidate, post-check=0, pre-check=0', 'Pragma': 'public'}

[孜孜求良师]

你用谷歌访问这个链接试下，下载的文件的文件名是中文的，如果没有设置请求头参数，响应正文里中文也不能正常显示，但是设置了请求头参数accept-language为：zh-cn，响应正文中文正常显示，响应headerfilename就成了乱码