@Override
    public AddPropertyStep<S> clone() {
        final AddPropertyStep<S> clone = (AddPropertyStep<S>) super.clone();
        clone.parameters = this.parameters.clone();
        return clone;
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/sideEffect/AddPropertyStep.java