input: Write a function to implement a chatbot in Python that can provide customer support in a restaurant. The function should take a user's question as input and return a randomly selected appropriate response from a predefined list. If the input file is empty, the function should return a default message indicating no question was provided.
  
  assert chatbot("What meals do you serve?") in [
   '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?'
  ]
  assert chatbot("") == "No question provided."
  assert chatbot("What is your phone number?") == "I'm sorry, I can't answer that question."
output: import random
  
  def chatbot(question):
      responses = {
          "What meals do you serve?": [
              '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?'
          ],
          "": ["No question provided."],
          "default": ["I'm sorry, I can't answer that question."]
      }
      
      if question in responses:
          return random.choice(responses[question])
      else:
          return random.choice(responses["default"])