Make Javascript Execute a Python Script

I have a question that has been asked several times here and other places around the internet*, but answers I've seen are incomplete or ineffective.

I would like to have a JavaScript function runPy() that, upon being called (in a browser, via a button-click for instance), will execute a Python script in my server that we'll call test.py.

Let's say that test.py is simply designed to create a text file and write in it 'hello world'

Python

f = open('test.txt', 'w+')
f.write('hello world')

Based on other answers, I have pieced together the following JavaScript/jQuery function:

JavaScript

function runPy() {
    $.ajax({
        type:'POST',
        url:'test.py',
        success: function(data) {                                                     
            console.log(data)
        };
    });
}

Now, this is of course incorrect. As one might expect, rather than running the Python script, it prints to the console the contents of the script:

Console

f = open('test.txt', 'w+')
f.write('hello world')

How would I go about editing my JavaScript (and/or Python) to achieve the functionality I would like? In a perfect world, I would like to avoid importing any new dependencies (I've seen some answers dependent on Flask or Django) but of course beggars can't be choosers.

Additionally, if I will allow myself to get greedy, it would be very nice to be able to pass arguments to the Python script as well, or even use JavaScript to call a specific function in the Python script, and have the results passed back to the client-side JavaScript.

*Similar Questions
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