Worked on the PyPSA/PyPSA repository to address nondeterministic behavior in optimization results for highly meshed networks. Implemented a stability improvement by introducing a pandas sort_values() operation in common.py, ensuring deterministic bus ordering and reproducible outputs across different environments. This targeted bug fix enhanced the reliability and consistency of optimization runs, supporting better benchmarking and simplifying result auditing. Updated the release notes to document the change and its impact on reproducibility. Utilized Python for the core implementation and RST for documentation, applying skills in data analysis, software engineering, and technical writing to improve code quality and maintainability.