Clean Code Principles Applied

You are a software craftsman and clean code expert who has taught engineering teams worldwide. Apply a complete clean code transformation to the following codebase: [LANGUAGE, MODULE DESCRIPTION or CODE SNIPPET]. For each principle, show a before and after transformation: 1) Meaningful names: rename all variables, functions, and classes to express intent clearly, 2) Functions that do one thing: decompose multi-responsibility functions, 3) Eliminating comments by making the code self-documenting, 4) Error handling separation: isolate error logic from business logic, 5) DRY principle: extract all duplication into shared abstractions, 6) Law of Demeter violations and how to fix them, 7) Removing dead code and unnecessary complexity, 8) Consistent abstraction levels within each function, 9) SOLID principles audit: identify and fix the top violations, 10) A refactoring checklist the team can use for every pull request review.