input: Write a function to implement a basic virtual assistant using Python and Dialogflow. The function should continuously prompt the user for input, send the input to Dialogflow for intent detection, and print the response from Dialogflow. Ensure that the function handles the Dialogflow session and project ID appropriately.
  import dialogflow_v2 as dialogflow
  
  def virtual_assistant():
   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)
  
  assert virtual_assistant() is not None
output: def virtual_assistant():
   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)