input: Write a function to detect user intent using Dialogflow.
  assert detect_user_intent("What is your return policy?")['query_text'] == "What is your return policy?"
  assert detect_user_intent("What is your return policy?")['intent'] == "Default Welcome Intent"
  assert detect_user_intent("What is your return policy?")['fulfillment_text'] == "Our return policy lasts 30 days."
output: def detect_user_intent(text):
      import dialogflow_v2 as dialogflow
      from google.api_core.exceptions import InvalidArgument
  
      DIALOGFLOW_PROJECT_ID = 'your-project-id'
      DIALOGFLOW_LANGUAGE_CODE = 'en'
      SESSION_ID = 'current-user-id'
  
      session_client = dialogflow.SessionsClient()
      session = session_client.session_path(DIALOGFLOW_PROJECT_ID, SESSION_ID)
  
      text_input = dialogflow.types.TextInput(text=text, language_code=DIALOGFLOW_LANGUAGE_CODE)
      query_input = dialogflow.types.QueryInput(text=text_input)
  
      try:
          response = session_client.detect_intent(session=session, query_input=query_input)
      except InvalidArgument:
          raise
  
      return {
          'query_text': response.query_result.query_text,
          'intent': response.query_result.intent.display_name,
          'fulfillment_text': response.query_result.fulfillment_text
      }