input: 
  def virtual_assistant():
      """
      Create a virtual assistant using Python and Dialogflow to answer a basic set of questions.
      This function sets up a session with Dialogflow, continuously prompts the user for input,
      and prints the assistant's response based on the input.
      >>> virtual_assistant()
      User: What is the weather today?
      Assistant: The weather today is sunny with a high of 75 degrees.
      User: Who is the president?
      Assistant: The current president is Joe Biden.
      """
      import dialogflow_v2 as dialogflow
      import requests
  
      project_id = 'project-id'
      session_client = dialogflow.SessionsClient()
      session = session_client.session_path(project_id, 'session-id')
  
      while True:
          text = input('User: ')
          text_input = dialogflow.types.TextInput(text=text, language_code='en-US')
          query_input = dialogflow.types.QueryInput(text=text_input)
          response = session_client.detect_intent(session=session, query_input=query_input)
  
          print('Assistant:', response.query_result.fulfillment_text)
  
output:     if text.lower() == 'exit':
          break