@Override
        public Traversal<Integer, Number> get_g_injectXnull_10_5_nullX_sum() {
            return g.inject(null, 10, 5, null).sum();
        }
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/SumTest.java