input: Write a python function to create a custom chatbot response based on user query intents.
  assert chatbot_query('hello') == 'Hello, how can I help you?'
  assert chatbot_query('bye') == 'Goodbye and have a nice day!'
  assert chatbot_query('unknown') == 'I am sorry, I don\'t know what you mean.'
output: def chatbot_query(query):
      if query == 'hello':
          return 'Hello, how can I help you?'
      elif query == 'bye':
          return 'Goodbye and have a nice day!'
      else:
          return 'I am sorry, I don\'t know what you mean.'