Worked on the django/django repository to enhance the reliability of Django’s ORM when handling None values in complex query scenarios. Focused on backend development using Python and Django, addressing edge cases in exclude(__in) lookups for nullable fields and composite primary key queries. Fixed a longstanding issue by refining how None is processed in query filters, ensuring accurate results for production applications. Collaborated closely with project reviewers and built on prior work to stabilize the solution. Expanded automated test coverage to reduce regression risk, emphasizing robust testing practices and long-term stability for applications relying on Django’s ORM query composition.