docs: function listTopics(res) {
      loadList(res.robot.brain); // Not necessary, but helps for testing.
      if (taboo.size == 0) {
        res.reply("Nothing is taboo here.");
      } else {
        let topics = [];
        taboo.forEach((re, topic) => {
          topics.push(topic);
        })
        res.reply("Taboo topics are: " + topics.join(", "));
      }
    }