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).

Eric Idle has not appeared on Broadway. How many West End shows has Eric Idle been in? Eric Idle has appeared on London's West End in 1 shows. What was Eric Idle's first West End show? Eric Idle's ...