Example code for using python handlers to set dynamic headers?

I'd like to use wptserve to set dynamic headers and include a static page
body.

Can anyone offer a recommendation on the best and most current working
example of this in the repo I can use as a guideline/template?

I'm trying to experiment with EventSource and CORS, but the tests that seem
to depend on .py files are reporting a lot of failures and timeouts for me
on Chrome Canary, so I'm not sure they're actually working correctly...

thanks,

Brad