@Override
    public List<Traversal.Admin<S, E>> getGlobalChildren() {
        return Collections.unmodifiableList(Stream.concat(
                this.traversalPickOptions.values().stream().flatMap(List::stream),
                this.traversalOptions.stream().map(Pair::getValue1)).collect(Collectors.toList()));
    }
@author Marko A. Rodriguez (http://markorodriguez.com)
@author Daniel Kuppitz (http://gremlin.guru)
gremlin-core/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/step/branch/BranchStep.java