def get_lag_by_topic_list(self, group_name, topics):
    self.lag_topics_found = []
    self.lag_total = 0

    topics = list(topics)
    no_threads = 16

    batches = [topics[i:i + no_threads] for i in range(0, len(topics), no_threads)]
    for batch_topics in batches:
        threads = []
        for topic in batch_topics:
            t = threading.Thread(target=self.get_lag_by_topic, args=(group_name, topic,))
            threads.append(t)
            t.start()

        for t in threads:
            if t.isAlive():
                t.join()

    return self.lag_total, list(set(self.lag_topics_found))