Month: 2025-03 – Monthly work summary focusing on key accomplishments across huggingface/trl and huggingface/course. Key deliverables include: 1) Multi-task reward functions support in GRPOTrainer enabling per-task rewards (that can return None) with robust aggregation, logging, and None-value handling; introduced unit tests and docs. 2) Test infrastructure and developer tooling improvements for GRPOTrainer (enhanced test setup, artifact cleanup, pre-commit formatting, updated docs). 3) GRPO Documentation Chapter: Creation and Enhancements in the course repo with new chapter, references, formatting, and clearer examples. These efforts improve multi-task RL training capabilities, code quality, testing safety, and documentation quality. Technologies used: Python, unit testing, pre-commit tooling, and documentation practices.