/**
* last strip id fetched in this comic collection so we only retrieve the new one
*
* @param comic
* @return last fetched strip id or if no strip at all, the string "unknown"
*/
@NonNull
private String getLastId(String comic) {
String lastId = cache.lastStripId(comic);
if (lastId == null) {
lastId = "unknown";
}
return lastId;
}
@Override
public Observable<List<Strip>> model(String comic) {
return cache.listStrips(comic);
}