/* 
 * 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) {