class BullyMessageManager extends AbstractMessageManager {

  /**
   * Constructor of BullyMessageManager.
   */
  public BullyMessageManager(Map<Integer, Instance> instanceMap) {
    super(instanceMap);
  }

  /**
   * Send heartbeat message to current leader instance to check the health.
   *
   * @param leaderId leaderID
   * @return {@code true} if the leader is alive.
   */
  @Override
  public boolean sendHeartbeatMessage(int leaderId) {
    var leaderInstance = instanceMap.get(leaderId);
    var alive = leaderInstance.isAlive();
    return alive;
  }

  /**
   * Send election message to all the instances with smaller ID.
   *
   * @param currentId Instance ID of which sends this message.
   * @param content   Election message content.
   * @return {@code true} if no alive instance has smaller ID, so that the election is accepted.
   */
  @Override
  public boolean sendElectionMessage(int currentId, String content) {<FILL_FUNCTION_BODY>}

  /**
   * Send leader message to all the instances to notify the new leader.
   *
   * @param currentId Instance ID of which sends this message.
   * @param leaderId  Leader message content.
   * @return {@code true} if the message is accepted.
   */
  @Override
  public boolean sendLeaderMessage(int currentId, int leaderId) {
    var leaderMessage = new Message(MessageType.LEADER, String.valueOf(leaderId));
    instanceMap.keySet()
        .stream()
        .filter((i) -> i != currentId)
        .forEach((i) -> instanceMap.get(i).onMessage(leaderMessage));
    return false;
  }

  /**
   * Send heartbeat invoke message to the next instance.
   *
   * @param currentId Instance ID of which sends this message.
   */
  @Override
  public void sendHeartbeatInvokeMessage(int currentId) {
    var nextInstance = this.findNextInstance(currentId);
    var heartbeatInvokeMessage = new Message(MessageType.HEARTBEAT_INVOKE, "");
    nextInstance.onMessage(heartbeatInvokeMessage);
  }

  /**
   * Find all the alive instances with smaller ID than current instance.
   *
   * @param currentId ID of current instance.
   * @return ID list of all the candidate instance.
   */
  private List<Integer> findElectionCandidateInstanceList(int currentId) {
    return instanceMap.keySet()
        .stream()
        .filter((i) -> i < currentId && instanceMap.get(i).isAlive())
        .toList();
  }

}

    var candidateList = findElectionCandidateInstanceList(currentId);
    if (candidateList.isEmpty()) {
      return true;
    } else {
      var electionMessage = new Message(MessageType.ELECTION_INVOKE, "");
      candidateList.stream().forEach((i) -> instanceMap.get(i).onMessage(electionMessage));
      return false;
    }
  
<methods>public void <init>(Map<java.lang.Integer,com.iluwatar.leaderelection.Instance>) <variables>protected Map<java.lang.Integer,com.iluwatar.leaderelection.Instance> instanceMap