protected void addMetaDataToNetwork(Network network) {
   if (networkMetadata.size() == 0) {
     return;
   }
   Tuple metadata = new Tuple();
   Set<String> keys = networkMetadata.keySet();
   for (Iterator<String> it = keys.iterator(); it.hasNext(); ) {
     String key = it.next();
     metadata.addSingle(new Single(key, networkMetadata.get(key)));
   }
   network.setMetadata(metadata);
 }
 public void addNetworkMetadata(String key, String value) {
   networkMetadata.put(key, value);
 }