if(log.isDebugEnabled()) {
if(log.isErrorEnabled()) {
  public Subgraph[] createRankedSubgraphs(int numberOfSubgraphs) {    Node lastNode = null;    Subgraph[] subgraphs = new Subgraph[numberOfSubgraphs];    for (int i = 0; i < numberOfSubgraphs; i++) {      subgraphs[i] = new Subgraph(this);      subgraphs[i].setAttribute(RANK_ATTRIBUTE, RANK_SAME);      Node node = new Node(subgraphs[i], String.valueOf(i));      node.setAttribute(INVISIBLE_ATTRIBUTE, "true");      node.visible = false;      if (lastNode != null) {	Edge edge = null;	try {	  edge = new Edge(this, lastNode, node);	} catch (RuntimeException e) {          if(log.isDebugEnabled()) {            log.error("Couldn't create edge from: " +                      lastNode + " " +                      node + " " + e);          }          continue;	} 	edge.setAttribute(INVISIBLE_ATTRIBUTE, "true");	edge.visible = false;      }      lastNode = node;    }    return subgraphs;  }