input: Write a function to implement a virtual assistant using Python and Dialogflow to answer a basic set of questions. The function should continuously prompt the user for input, send the input to Dialogflow for processing, and then print the response from the assistant.
  import dialogflow_v2 as dialogflow
  import requests
  
  project_id = 'project-id'
  session_client = dialogflow.SessionsClient()
  session = session_client.session_path(project_id, 'session-id')
  
  def virtual_assistant():
      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)
  assert virtual_assistant() is None
output: def virtual_assistant():
      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)