/* See if a piece of information exists in data returned by a successful query by a MusicBrainz::Client object.
*
* Note: Certain result queries require an ordinal argument. See the
* MusicBrainz result query (MBE_*) documentation for additional
* information.
*
* Aliases:
* MusicBrainz::Client#result_exists?
* MusicBrainz::Client#does_result_exist?
*
* Examples:
* # does the current album have a name?
* puts 'named album' if mb.exists? MusicBrainz::Query::AlbumGetAlbumName
*
* # does the current album have a type?
* puts 'has a type' if mb.exists? MusicBrainz::Query::AlbumGetAlbumType
*/
static VALUE mb_client_exists(int argc, VALUE *argv, VALUE self) {