如何在RASA聊天机器人中跟踪每一步所用的时间

from datetime import datetime

class TrackTimeAction(Action):
    def name(self) -> Text:
        return "action_track_time"

    def run(self, dispatcher: CollectingDispatcher,
            tracker: Tracker,
            domain: Dict[Text, Any]) -> List[Dict[Text, Any]]:
        
        # 获取当前时间戳
        current_time = datetime.now()
        
        # 获取上一步的时间戳
        prev_time = tracker.get_slot("prev_time")
        
        # 计算时间差
        if prev_time:
            time_diff = current_time - prev_time
            time_diff_seconds = time_diff.total_seconds()
        else:
            time_diff_seconds = 0
        
        # 将时间差添加到对话历史中
        tracker.update(UserUttered(text=f"Time taken: {time_diff_seconds} seconds"))
        
        # 更新当前时间戳
        tracker.update_slot("prev_time", current_time)
        
        return []