@Override
  public Iterable<ReferenceID> getIndexedDependencies(Node<?, ?> node) {
    ReferenceID nodeID = node.getReferenceID();
    return Iterators.unique(Iterators.map(Iterators.filter(node.getUsages(), u -> !nodeID.equals(u.getElementOwner())), u -> u.getElementOwner()));
  }
@Override
  public Iterable<ReferenceID> getIndexedDependencies(Node<?, ?> node)