Worked on the Optuna/optuna repository to enhance the PercentilePruner component, focusing on improving code readability and debugging efficiency. Consolidated related changes into a single feature by refactoring string formatting in _percentile.py from .format to Python f-strings, which streamlined the codebase and improved maintainability. Enhanced error messages to include variable names, making it easier for developers to identify and reproduce issues during backend development. The work emphasized code optimization, refactoring, and robust error handling, contributing to faster debugging and more reliable pruning workflows. No user-facing bugs were addressed, as the primary focus was on internal developer productivity and code quality.