send requests to URL with proxy

[jpmo02]

Hello
I want to send a POST/GET request to an URL
I use from Requests module and create a Session
and send my requests with this session

Please help me to send this request with a Proxy (proxy is annonymouse and without user/pass)

I Test these three way but can't get answer (Of course maybe I made a mistake!)
Way 1:

session.proxies = {pr: ip + ":" + port}

Way 2:

proxy = {pr: ip + ":" + port}
s = session.post(link, data, proxies=proxy, headers=head)

Way 3:

req = requests.Request('POST', link, data=data, headers=head)
prepped = req.prepare()
resp = session.send(prepped, proxies=proxy)

Please help me or say to me a different way
Thanks a lot