docs: private Collection<EqClassT> getAlignedTo(final Object item) {
      if (rightEquivalenceClassesToProvenances.containsKey(item)
          && leftEquivalenceClassesToProvenances.containsKey(item)) {
        return ImmutableList.of((EqClassT) item);
      } else {
        return ImmutableList.of();
      }
    }