@Override
        public Traversal<Vertex, Map<Long, Map<String, List<Vertex>>>> get_g_V_group_byXbothE_countX_byXgroup_byXlabelXX() {
            return g.V().<Long, Map<String, List<Vertex>>>group().by(bothE().count()).by(__.group().by(T.label));
        }
@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