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).

Upon opening a Command Prompt, you will see a file path (e.g., "C:\Users\Chifundo"). This is called the prompt, and it shows what directory you're currently in. The blinking cursor at the end ...