@Override
    public void modulateBy(final Traversal.Admin<?, ?> selectTraversal) {
        this.traversalRing.addTraversal(this.integrateChild(selectTraversal));
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/map/ProjectStep.java