Room for Aladdin and John Rennie

You don't care whether the attainable set excludes more than one number.

blog.quest.com/an-overview-of-sql-join-types-with-examples

But it works with a full file name as well. So D:\rhs\Python\test.py\.. effectively goes up one level from the file, and that's the directory D:\rhs\Python

I use it to run my mail server and my file server and also a copy of Windows 10 I can dial into when I'm away from home.

with open(filename,'w', newline='') as csvfile:
    csvwriter=csv.writer(csvfile, lineterminator=os.linesep)
    csvwriter.writerow(fields)
    csvwriter.writerows(rows)