Joshua Frost enhanced the NHSDigital/manage-vaccinations-in-schools-testing repository by delivering targeted type-safety and readability improvements to its backend modules. Focusing on Python and leveraging type hinting, he updated the year_groups parameter in pg_import_records.py from an optional integer to an optional list of integers, enabling more robust compile-time checks and supporting future feature expansion. In pg_login.py, he removed a strict return type annotation from try_invalid_login, increasing flexibility for downstream integrations. Although no critical bugs were addressed, Joshua’s work prioritized preventive quality, improving maintainability and onboarding for contributors while laying a foundation for faster, more reliable backend development.