input: Write a python function to implement a simple chatbot using Rasa that can handle movie booking intents.
  assert booking_movies(None, None, None) == [SlotSet('movietitle', None)]
  assert booking_dates(None, None, None) == [SlotSet('moviedate', None)]
  assert booking_times(None, None, None) == [SlotSet('movietime', None)]
  assert booking_confirmation(None, None, None) == []
output: from rasa_sdk import Action, Tracker
  from rasa_sdk.executor import CollectingDispatcher
  from rasa_sdk.events import SlotSet
  
  class ActionBookMovie(Action):
  
      def name(self) -> str:
          return "action_book_movie"
  
      def run(self, dispatcher: CollectingDispatcher,
              tracker: Tracker,
              domain: dict) -> list:
  
          movietitle = tracker.get_slot('movietitle')
          moviedate = tracker.get_slot('moviedate')
          movietime = tracker.get_slot('movietime')
  
          if not movietitle:
              dispatcher.utter_message(text="Which movie would you like to book?")
              return [SlotSet('movietitle', None)]
          
          if not moviedate:
              dispatcher.utter_message(text="For which date would you like to book the movie?")
              return [SlotSet('moviedate', None)]
  
          if not movietime:
              dispatcher.utter_message(text="What time would you like to watch the movie?")
              return [SlotSet('movietime', None)]
  
          dispatcher.utter_message(text=f"Booking movie '{movietitle}' on {moviedate} at {movietime}.")
          return []
  
  def booking_movies(dispatcher, tracker, domain):
      action = ActionBookMovie()
      return action.run(dispatcher, tracker, domain)
  
  def booking_dates(dispatcher, tracker, domain):
      action = ActionBookMovie()
      return action.run(dispatcher, tracker, domain)
  
  def booking_times(dispatcher, tracker, domain):
      action = ActionBookMovie()
      return action.run(dispatcher, tracker, domain)
  
  def booking_confirmation(dispatcher, tracker, domain):
      action = ActionBookMovie()
      return action.run(dispatcher, tracker, domain)