os.path.join (folder, filename) ensures the path is correct for the system. On Windows, it uses backslashes (reports\summary.txt); on Linux and macOS it uses forward slashes (reports/summary.txt).

Is it possible to install python on Mac OS without the need of conda, pyenvy, and home-brew? Will having python installed without some type of virtual environment effect anything that is related to ...

Modern Python developers use virtual environments (venvs), to keep their projects and dependencies separate. Managing project dependencies gets more complex as the number of dependencies grows.