@Override
        public Traversal<Vertex, Map<String, Long>> get_g_V_groupXmX_byXlabelX_byXlabel_countX_capXmX() {
            return g.V().group("m").by(__.label()).by(__.label().count()).cap("m");
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
@author Stephen Mallette (http://stephen.genoprime.com)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/sideEffect/GroupTest.java