teachable.py add a section-title

[Ghaleb-alnakhlani]

Checklist

• I'm reporting a site feature request
• I've verified that I'm running youtube-dl version 2020.03.08
• I've searched the bugtracker for similar site feature requests including closed ones

Description

Simply i want to add section-title (similar to chapter in udemy). I tried to do it with "self._html_search_regex" but I couldn`t do it because I did not understand the python code.
Everything is working perfectly except when I want to output %(chapter)s/%(title)s.%(ext)s
it will output NA for chapter.

I managed to get the regex from the HTML for section_title

r'<span[^>]+class=["']section-lock[^>]+>\s*<i[^>]+class=["']fa\sfa-lock[^>]+> \s*[^>]+>\s*(.+)'

But i don`t know how to add it to the teachable.py

the website I am trying to download from is zerotomastery.io

[Ghaleb-alnakhlani]

I have marked what I want to extract exactly. To make the issue more clear.