Worked on enhancing the robustness of Twister in the renesas/zephyr repository by addressing error handling for missing dependencies. Focused on backend development using Python, the developer implemented a try-except block around the serial library import, ensuring that Twister would not crash if the optional library was absent. This change prevented test automation failures in CI pipelines, reducing downtime and support requests. The solution was delivered as a single, well-documented commit, improving maintainability and traceability for future updates. The work demonstrated careful attention to reliability and error handling, contributing to a smoother experience for users running automated tests.