input: Write a function to generate responses based on input messages using specific criteria.
  assert respond("hello") in ["Hello!", "Hi there!", "Nice to meet you!", "Checking in."]
  assert respond("good morning") in ["Hello!", "Hi there!", "Nice to meet you!", "Checking in."]
  assert respond("how are you?") == "Sorry, I don't have the answer to that yet."
  assert respond("where are you?") == "Sorry, I don't have the answer to that yet."
  assert respond("random message") in ["I'm not sure I understand you fully.", "Please provide more information.", "What do you mean by that?", "Can you be more specific?"]
output: def respond(message):
      greetings = ["hello", "hi", "good morning", "good afternoon", "good evening"]
      unknown_responses = ["I'm not sure I understand you fully.", "Please provide more information.", "What do you mean by that?", "Can you be more specific?"]
      specific_responses = {
          "how are you?": "Sorry, I don't have the answer to that yet.",
          "where are you?": "Sorry, I don't have the answer to that yet."
      }
      
      message_lower = message.lower()
      
      if message_lower in greetings:
          return "Hello!"
      elif message_lower in specific_responses:
          return specific_responses[message_lower]
      else:
          return "I'm not sure I understand you fully."