input: 
  from typing import List
  
  def generate_response(utterance: str, model) -> str:
      """Given a sample utterance and a pre-trained model, generate a natural language response.
      >>> generate_response("What time is it?", model)
      'The time is currently 3:45 PM.'
      >>> generate_response("How are you?", model)
      'I am functioning within expected parameters.'
      """
      pass
  
output:     response = model.generate_response(utterance)
      return response