If we accept the value syntax in my protocol document, keywords must start with
an ALPHA so that they are distinguishable from integer. So the extension-code
should not be a type 2 keyword, though it may be a type 2 integer.
> (8) ISSUE:
> Since multiple documents isn't indicated by an attribute, but rather
> by the content that is sent, we need a distinct error code:
>
> multiple-documents-not-supported
>
There is another way around this problem. If we believe that jobs are
always encoded in MIME, then the attribute formats-supported contains
values, such as application/postscript and application/vnd.hp-PCL. If
the formats-supported attribute also contains a value of
multipart/mixed, then the Printer accepts multiple documents.