docs: private String determineSlotSharingGroup(String specifiedGroup, Collection<Integer> inputIds) {
  		if (specifiedGroup != null) {
  			return specifiedGroup;
  		} else {
  			String inputGroup = null;
  			for (int id: inputIds) {
  				String inputGroupCandidate = streamGraph.getSlotSharingGroup(id);
  				if (inputGroup == null) {
  					inputGroup = inputGroupCandidate;
  				} else if (!inputGroup.equals(inputGroupCandidate)) {
  					return "default";
  				}
  			}
  			return inputGroup == null ? "default" : inputGroup;
  		}
  	}