Class MediaTray is a subclass of Media.
Class MediaTray is a printing attribute class, an enumeration, that
specifies the media tray or bin for the job.
This attribute can be used instead of specifying MediaSize or MediaName.
Class MediaTray declares keywords for standard media kind values.
Implementation- or site-defined names for a media kind attribute may also
be created by defining a subclass of class MediaTray.
IPP Compatibility: MediaTray is a representation class for
values of the IPP "media" attribute which name paper trays.