question: public boolean unSubscribeTopic ( @ NonNull Context context , @ NonNull String [ ] removeTopics ) { if ( ! initialized ) init ( context ) ; if ( removeTopics . length == 0 ) return false ; for ( String topic : removeTopics ) { topics . remove ( topic ) ; } Intent intent = new Intent ( context , RegistrationIntentService . class ) ; intent . setAction ( RegistrationIntentService . ACTION_UNSUBSCRIBE ) ; intent . putExtra ( RegistrationIntentService . EXTRA_TOPIC_LIST , removeTopics ) ; context . startService ( intent ) ; return true ; }
target:  Un-subscribe from specific topics