throw new UnsupportedOperationException();
  }

  @Override
  public int size() {
    if (graph.isDirected()) {
      return predecessorsOrEmpty(node).size()
          + successorsOrEmpty(node).size()
          - (edgeType == EdgeType.BOTH && predecessorsOrEmpty(node).contains(node) ? 1 : 0);
    } else {
      return graph.adjacentNodes(node).size();
    }
  }

  @Override

    throw new UnsupportedOperationException();
  }

  @Override
  public int size() {
    if (graph.isDirected()) {
      return predecessorsOrEmpty(node).size()
          + successorsOrEmpty(node).size()
          - (edgeType == EdgeType.BOTH && predecessorsOrEmpty(node).contains(node) ? 1 : 0);
    } else {
      return graph.adjacentNodes(node).size();
    }
  }

  @Override