Julien Palard added the comment:
> If we were able to pass an instance of SimpleHTTPRequestHandler instead of its class, we'd be able to give the `directory` to the handler during the `main()`, instead of using with `chdir` and `getcwd` to pass the information in a kind of hidden/side channel.

You may be able to use functools.partial() to pass an additional
parameter to the request handler constructor.

We use something like that in asyncio for protocols.