input: Write a function to create a virtual assistant using Python and Dialogflow that will answer a basic set of questions. The function should keep running and process user input until manually stopped.
  
  assert virtual_assistant()=='import dialogflow_v2 as dialogflow\nimport requests\n\nproject_id = \'project-id\'\nsession_client = dialogflow.SessionsClient()\nsession = session_client.session_path(project_id, \'session-id\')\n\nwhile True:\n text = input(\'User: \')\n text_input = dialogflow.types.TextInput(text=text, language_code=\'en-US\')\n query_input = dialogflow.types.QueryInput(text=text_input)\n response = session_client.detect_intent(session=session, query_input=query_input)\n\n print(\'Assistant:\', response.query_result.fulfillment_text)'
  
  assert virtual_assistant()!=''
  
  assert virtual_assistant()!='This is not the correct implementation.'
output: 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)