@Override
 public boolean execute(TextUI console, Iterator<String> args) throws IllegalParametersException {
   Set<String> replicas = JDG.replicaValuesFromKeys(cache);
   for (String key : replicas) {
     console.println(key);
   }
   console.println("Cache Size: " + cache.size() + "\n");
   console.println("Replica Size: " + replicas.size() + "\n");
   return true;
 }
 @Override
 public void usage(TextUI console) {
   console.println(COMMAND_NAME);
   console.println("\t\tList all local valuesFromKeys for which this node is a replica.");
 }