List<MetadataGraphEdge> ins = getIncidentEdges(v);
            if (ins != null) {
                for (MetadataGraphEdge e : ins) {
                    sb.append("       from :  ").append(e.toString()).append('\n');
                }
            } else {
                sb.append("      no entries\n");
            }

            List<MetadataGraphEdge> outs = getExcidentEdges(v);