Worked on the facebook/fbthrift repository with a focus on improving the stability and correctness of core data structures. Addressed a bug in the MutableList insert method by correcting the internal type used, which restored proper insertion behavior and reduced the risk of edge-case failures in downstream code. The solution was delivered as a precise, traceable fix linked to a single commit, demonstrating attention to code quality and maintainability. Utilized Python and applied expertise in data structures and unit testing to ensure the repository’s reliability. This work enhanced the robustness of a fundamental operation, minimizing potential defects and support overhead.