Improving type safety in Rucio

This report covers my contribution to the Rucio project during my eight weeks at CERN from June 20th to August 12th 2022. Rucio is an open source distributed data management system initially built to serve the ATLAS experiment's needs, but is now also used in other scientific experiments like CMS and DUNE. Rucio is written in Python, and in June 2022 ended support for Python 2.7. This allows the introduction of Python type annotations throughout the codebase, which was part of my work.