input: Write a Python function to process a message and answer a query based on the presence of the word "refund".
  assert answer_query("Can I get a refund for my defective product?") == 'Yes, you can get a refund if your product is defective.'
  assert answer_query("What is your return policy?") == 'Sorry, I can\'t answer that question.'
  assert answer_query("How can I get a refund?") == 'Yes, you can get a refund if your product is defective.'
  assert answer_query("Is my product eligible for a refund?") == 'Yes, you can get a refund if your product is defective.'
output: def answer_query(message: str) -> str:
      if "refund" in message.lower():
          return 'Yes, you can get a refund if your product is defective.'
      else:
          return 'Sorry, I can\'t answer that question.'