input: Write a function to implement a chatbot in Python that can provide customer support in a restaurant. The function should read a user question from a file named 'random_user_question.txt' and provide a random response from a predefined list of possible responses. If the file is empty or does not contain a question, the function should return a default message indicating no question was found.
  def restaurant_chatbot():
      possible_responses = [
          'We serve a variety of dishes - from salads to pizzas to steaks!',
          'Check out our menu for a full list of options',
          'We serve a variety of dishes, including traditional Italian, Mexican, and American fare. What would you like to try?',
          'We have a great selection of meals! What kind of dish are you looking for?',
          'We have a unique selection of meals - have you checked out our menu?'
      ]
  
      try:
          with open('random_user_question.txt') as user_question:
              question = user_question.read().strip()
              if not question:
                  return "No question found in the file."
      except FileNotFoundError:
          return "File not found."
  
      return random.choice(possible_responses)
  
  assert restaurant_chatbot()=='We serve a variety of dishes - from salads to pizzas to steaks!'
  assert restaurant_chatbot()=='Check out our menu for a full list of options'
  assert restaurant_chatbot()=="No question found in the file."
  assert restaurant_chatbot()=='File not found.'
output: def restaurant_chatbot():
      possible_responses = [
          'We serve a variety of dishes - from salads to pizzas to steaks!',
          'Check out our menu for a full list of options',
          'We serve a variety of dishes, including traditional Italian, Mexican, and American fare. What would you like to try?',
          'We have a great selection of meals! What kind of dish are you looking for?',
          'We have a unique selection of meals - have you checked out our menu?'
      ]
  
      try:
          with open('random_user_question.txt') as user_question:
              question = user_question.read().strip()
              if not question:
                  return "No question found in the file."
      except FileNotFoundError:
          return "File not found."
  
      return random.choice(possible_responses)