Reading through your documentation you say you've disable HTTP_PROXY for pypi because it's an HTTPS request. I may have missed the code change, but if you're still using ProxyHandler, that isn't related to the HTTP_PROXY and HTTPS_PROXY variables which I believe you're referencing in your README. ProxyHandler with work with proxied requests to both http and https sites.
Reading through your documentation you say you've disable HTTP_PROXY for pypi because it's an HTTPS request. I may have missed the code change, but if you're still using ProxyHandler, that isn't related to the HTTP_PROXY and HTTPS_PROXY variables which I believe you're referencing in your README. ProxyHandler with work with proxied requests to both http and https sites.