Can't understand htmlpy GUI library?

Question

Python

There is a library for creating a gui for python using html, there are only 3 pages in the documentation, I understood how to display an html page in the program window, but how to make it so that I have a button on the html page and when this button is pressed, the functions are executed in python? It's sort of like it says on this page, but I don't understand what happens until the end of htmlpy.readthedocs.io/en/master/tutorials.html#gui... starting with what they import in the third line.

Answer 1

To find out what's going on - you need to read the source