public boolean existsAgent(ClusterIdentifier agcid) {   return agents.contains(new Agent(agcid));
public boolean existsAgent(String ag) {   return agents.contains(new Agent(ag));
  public boolean existsAgent(ClusterIdentifier agcid) {    // Agents are the same if their ClusterIdentifiers are the same    //return (getAgent(agcid) != null);    return agents.contains(new Agent(agcid));  }