Mercurial is a distributed open source source control (also known as "version control") system for tracking and handling file modifications. Mercurial can be used as the version control system for Python projects.
Hg Init is a six-part in-depth tutorial that explores the basic concepts and syntax for using Mercurial.
The official Mercurial tutorial goes through the basics. It has great examples for syntax and expected output.
Monoroke is a Mercurial server written in Rust designed to be used for very large monorepos that have thousands of commits affecting millions of files per hour.