@Override
        public Traversal<Vertex, Map<String, Collection<String>>> get_g_V_hasXlangX_groupXaX_byXlangX_byXnameX_out_capXaX() {
            return g.V().has("lang").group("a").by("lang").by("name").out().cap("a");
        }
@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