Explore the process of refactoring a monolithic Python function into smaller, modular, and testable components in this 26-minute tutorial. Learn essential mental models for writing modular Python functions, enhancing code maintainability, testability, and predictability. Follow along as the instructor demonstrates breaking down a large function into several smaller ones, ideal for unit testing. This video is part of a series on building a Python package for a terminal-based productivity tool. For a comprehensive learning experience, consider watching the full playlist, which includes previous episodes on TaskWarrior, command-line productivity scoreboards, and publishing Python packages. Access the code repository on GitHub and the published package on PyPI to practice implementing these concepts in your own projects.