@Override
        public void reduce(Integer key, Iterator<Integer> values, ReduceEmitter<Integer, Integer> emitter) {
            values.forEachRemaining(i -> emitter.emit(i, 1));
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/computer/GraphComputerTest.java