@Override
        public Traversal<String, Object> get_g_withSideEffectXk_nullX_injectXxX_selectXkX() {
            return g.withSideEffect("k",null).inject("x").select("k");
        }
@author Marko A. Rodriguez (http://markorodriguez.com)
@author Stephen Mallette (http://stephen.genoprime.com)
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/SelectTest.java