private <T> void flattenHelper( Flatten.PCollections<T> transform, TranslationContext context) { StepTranslationContext stepContext = context.addStep(transform, "Flatten"); List<OutputReference> inputs = new ArrayList<>(); for (PValue input : context.getInputs(transform).values()) { inputs.add(context.asOutputReference(input, context.getProducer(input))); } stepContext.addInput(PropertyNames.INPUTS, inputs); stepContext.addOutput(PropertyNames.OUTPUT, context.getOutput(transform)); } });