Worked on the litestar-org/litestar repository to enhance multipart upload reliability by addressing a validation issue in file handling. Focused on backend and API development using Python, the work involved fixing a bug where empty strings in multipart forms were incorrectly treated as files, leading to unnecessary 400 errors. The solution converted empty strings to None for Optional[UploadFile] fields, reducing edge-case failures and improving both developer and end-user experience. Type annotations were added to satisfy mypy, and the logic for Optional[UploadFile] checks was refactored for clarity and maintainability, emphasizing robust testing and type-safety throughout the process.