@interface _DKNowPlayingMetadataKey : NSObject + (id)iTunesSubscriptionIdentifier; + (id)isAirPlayVideo; + (id)playing; + (id)iTunesStoreIdentifier; + (id)outputDeviceIDs; + (id)genre; + (id)identifier; + (id)album; + (id)elapsed; + (id)artist; + (id)mediaType; + (id)title; + (id)duration; @end