@Override
    @SuppressWarnings("CloneDoesntCallSuperClone")
    public TrueTraversal<S> clone() {
        return INSTANCE;
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/lambda/TrueTraversal.java