如果你想为请求添加HTTP头部，只要简单地传递一个dict给headers参数就可以了

import requests

base_url = "http://httpbin.org"

form_data = {"user":"tumaowolf","password":"888999"}
header = {"user-agent":"Mozilla/5.0"}
r = requests.post(base_url+'/post',data=form_data,headers=header)
print(r.text)