@Override
    public DefaultGraphTraversal<S, E> clone() {
        return (DefaultGraphTraversal<S, E>) super.clone();
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/dsl/graph/DefaultGraphTraversal.java