src/main/java/org/intellimate/izou/sdk/frameworks/music/player/Playlist.java
public Optional<String> getData() {
        if (data == null) {
            return Optional.empty();
        } else {
            return Optional.of(data);
        }
    }
public Optional<String> getData() {
        if (data == null) {
            return Optional.empty();
        } else {
            return Optional.of(data);
        }
    }
returns the associated data (not really specified, specified by implementation)
@return the optional data-element