@Override
        public GraphComputer edges(Traversal<Vertex, Edge> edgeFilter) throws IllegalArgumentException {
            return this;
        }
@author Matthias Broecheler (me@matthiasb.com)
@author Marko A. Rodriguez (marko@markorodriguez.com)
gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/process/TraversalStrategiesTest.java