Programming pointer? -- options to run Python3 from web page (not via Flask/cgi/Django)

[deb <deb@rangingthoughts.org>]

I have a large static html/AJAX .js apache2 site.

If I want to have a server-side script just to
handle a contact <form> and push mail out;
is there a non-(Django/cgi**/Flask) way to
run a small Python3 script to do this?

The python3 mail script already works standalone (tests out fine from 
CLI, on the server).

I'd rather not Flask out the whole website just to get the ability to 
run one .py script for contact mail.

I'd rather not add .php to the server just to do this contact form.

** /cgi-bin to run the single python3 script is deprecated [Correct?].

It is a straight-up HTML5 form ... that USED to post to .aspx.
<form method="POST"  id='contactForm' action="  ?  " >


While I would prefer the answer to be python-ish,
it does to Have to be python.


Thank you!