Use upstream proxy without CONNECT

I’m forced to use an rather weird upstream proxy that doesn’t support CONNECT. To access https URLs, you have to use regular HTTP verbs (GET, PUT, POST, etc) just like if you were accessing http URLs. You cannot do the normal HTTPS proxy approach of opening a TCP tunnel using CONNECT. This means every normal clients (web browsers, curl, etc) are unable to access HTTPS resources through this proxy.

I’m trying to figure out how to get mitmproxy to act an HTTPS proxy that accepts CONNECT requests from “normal” clients (like web browsers and curl) and services the request using my non-CONNECT upstream proxy.

Is this possible? If so, how do I set up mitmproxy in this way?