public void choice(final PGroup group, final Map<String, Object> params, final List<DataflowWriteChannel<T>> outputs, final Closure<Integer> code) {
final Map<String, Object> parameters = new HashMap<String, Object>(params);
parameters.put("inputs", asList(this));
parameters.put("outputs", asList(outputs));
group.operator(parameters, new ChoiceClosure(code));
}