RFC977 3.5.1.  LAST

   LAST

   The internally maintained "current article pointer" is set to the
   previous article in the current newsgroup.  If already positioned at
   the first article of the newsgroup, an error message is returned and
   the current article remains selected.

   The internally-maintained "current article pointer" is set by this
   command.

   A response indicating the current article number, and a message-id
   string will be returned.  No text is sent in response to this
   command.

RFC977 3.5.2.  Responses

   223 n a article retrieved - request text separately
           (n = article number, a = unique article id)


   412 no newsgroup selected
   420 no current article has been selected
   422 no previous article in this group