tokens: As soon as none of those exist any more and the event queue is empty and the flow of control returns back to the system ( e.g . no JS is executing ) , then the node app will shut itself down .
ner_tags: O O O O O O O O O O O O B-Data_Structure O O O O O O O O O O O O O O O O B-Language O O O O O O B-Application O O O O O O