@eric.smith
It actually caused a problem and then turned into a curiosity. At the beginning I wanted to remind myself about the string module so I did a help(string). Then right after that I wrote a program that generated filenames from string.letters. I closed the python interpreter down and then reopened it and regenerated filenames again using string.letters. To my surprise I found the second iteration to come out with completely different results messing up my work. Once I found that help() was causing this problem and it became a curiosity because you would think help() would not modify anything. Obviously this problem is easy to work around in my case.