Usefulness of the "not in" operator

[Roy Smith]

In article <4e906108$0$27980$426a34cc at news.free.fr>,
 candide <candide at free.invalid> wrote:

> After browsing source code, I realize that parenthesis are not necessary 
> ("not" has higher precedence than "in").

Here's my take on parenthesis:  If you need to look up whether they're 
necessary or not, they are :-)