input: def generate_response(question: str) -> str:
      """Generate a response to a user query about a product or service. The function uses a predefined dictionary of answers for specific questions, and provides a set of fallback responses for unknown queries. The conversation continues until the user says 'Goodbye'.
      
      >>> generate_response('What is XYZ?')
      'XYZ is a company that provides XYZ services.'
      >>> generate_response('What does XYZ do?')
      'XYZ helps customers find solutions to their problems.'
      >>> generate_response('Where is XYZ located?')
      'XYZ is located in ABC city.'
      >>> generate_response('What are the benefits of using XYZ?')
      'XYZ provides a quick and easy way to find solutions to your problems.'
      >>> generate_response('Unknown question')
      'I am not sure I understand.'
      """
output:     predefined_answers = {
          'What is XYZ?': 'XYZ is a company that provides XYZ services.',
          'What does XYZ do?': 'XYZ helps customers find solutions to their problems.',
          'Where is XYZ located?': 'XYZ is located in ABC city.',
          'What are the benefits of using XYZ?': 'XYZ provides a quick and easy way to find solutions to your problems.'
      }
      
      fallback_responses = [
          'I am not sure I understand.',
          'Could you please rephrase your question?',
          'I am here to help, but I need more information.'
      ]
      
      if question in predefined_answers:
          return predefined_answers[question]
      else:
          import random
          return random.choice(fallback_responses)