During November 2024, Hao Wang enhanced the microsoft/presidio repository by delivering targeted REST API improvements for entity analysis. He introduced new parameters—allow_list, allow_list_match, and regex_flags—enabling users to filter and control entity recognition with greater precision. His technical approach centered on Python, leveraging regular expressions to support flexible matching strategies. To ensure reliability, Hao developed comprehensive end-to-end tests that validated the new API features across multiple scenarios. While the work focused on a single feature, it demonstrated depth through thoughtful parameter design and robust test coverage, reflecting strong skills in API development, regular expressions, and automated testing practices.