cefpython3. JS and Python connection

[ioprst]

Python 3.4. GUI - wxPython.
It is necessary to calculate the size of the text in pixels declared in the SVG document.

<svg viewBox="0 0 {width} {height}" xmlns="http://www.w3.org/2000/svg" id="svg" height="100%" width="100%">
  <text font-family="{font}" font-size="{size}" id="user_text">{text}</text>
</svg>

Using Python and wxPython does not work. wxPython allows you to determine the size, which will occupy the text with a specific font, size, etc., but they are not true for SVG (due to scaling of the svg-document, as I understood it).
Found a way to calculate text size via JS:

let text = document.getElementById("user_text");
let box = text.getBBox();
let w = box.width;
let h = box.height;

This solution gives the right result.
I need to use the values ​​computed in JS in my GUI program in Python.
The web engine built into wxPython doesn’t pull it (some old IE is there).
Advised cefpython3 library - Chromium Embedded Framework. It allows you to connect the browser to the GUI. It works fine.
As I understood from the tutorial, i can call JS methods from Python by first declaring them.
But I could not manage to implement the mechanism in any way, so that after executing the JS function, I would return the result back to Python and use it.
Is it even possible? If yes, please tell me which way to dig.