There's one line in there that's driving me nuts.

nobu / ruby-lang.org wrote:
> 
>   def adventurous!
>     verbose, $VERBOSE = $VERBOSE, nil
      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>     yield
>   ensure
>     $VERBOSE = verbose
>   end
> 
>   adventurous! {system(cmd)}
> 
What the heck is that line doing??