yth (Yes That Helped). You know how it goes, I thought I'd already tried to include all arguments. Obviously I didn't, or stuffed it up in some other way. Also some confusion about the meaning of "required" and "default". The doc explains these arguments as required, but some have defaults. I guess I thought if they had defaults then they didn't need to be specified.
Anyway, problem solved. Thanks again. -- http://mail.python.org/mailman/listinfo/python-list
