[Python-Dev] Lib/http/client.py: could it return an OSError with the current response?

Hi everybody, Sorry for bothering you, this is my first post to the python-dev ML. While using requests to tunnel a request via a proxy requiring user authentication, I have seen that httplib ( https://hg.python.org/cpython/file/3.5/Lib/http/client.py#l831) raises the message returned by the proxy, along with its status code (407) without including the proxy response. This one could be very interesting to the consumer, since it could contain some useful headers (like the supported authentication schemes). Would it be possible to change the http/client.py behavior in order to raise an exception including the whole response? If you don't see any problem with my proposal, how can I propose a pull request? :-) Thanks in advance, Ivo