input: Write a function to create a virtual assistant using Python and Dialogflow that can answer a basic set of questions. The function should use Dialogflow to detect the intent of the user's input and return the appropriate response. The function should continuously prompt the user for input and return the assistant's response until the user decides to exit.
  import dialogflow_v2 as dialogflow
  import requests
  
  def create_assistant(project_id, session_id):
      session_client = dialogflow.SessionsClient()
      session = session_client.session_path(project_id, session_id)
  
      while True:
          text = input('User: ')
          if text.lower() == 'exit':
              break
          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 create_assistant('project-id', 'session-id')==None
  assert create_assistant('another-project-id', 'another-session-id')==None
output: def create_assistant(project_id, session_id):
      session_client = dialogflow.SessionsClient()
      session = session_client.session_path(project_id, session_id)
  
      while True:
          text = input('User: ')
          if text.lower() == 'exit':
              break
          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)