Refactor 31 lines occurring 2 times in 2 files: drlg_l2.cpp, drlg_l4.cpp

I've selected for refactoring 31 lines of code which are duplicated in 2 file(s) (1, 2). Addressing this will make our codebase more maintainable and improve Better Code Hub's Write Code Once guideline rating! 👍

Here's the gist of this guideline:

• Definition 📖 Do not copy code.
• Why❓ When code is copied, bugs need to be fixed in multiple places. This is both inefficient and a source of regression bugs.
• How 🔧 Avoid duplication by never copy/pasting blocks of code and reduce duplication by extracting shared code, either to a new unit or introduce a superclass if the language permits.

You can find more info about this guideline in Building Maintainable Software. 📖

---

Good luck and happy coding! :shipit: :sparkles: :100: