@Override
    public List<HasContainer> getHasContainers() {
        return Collections.unmodifiableList(this.hasContainers);
    }
List of iterators opened by this step.
tinkergraph-gremlin/src/main/java/org/apache/tinkerpop/gremlin/tinkergraph/process/traversal/step/sideEffect/TinkerGraphStep.java