input: Write a function to create a virtual assistant using Python and Dialogflow to answer a basic set of questions. The function should continuously prompt the user for input, send it to Dialogflow for processing, and print the response from the assistant. The function should run indefinitely until manually interrupted. If no input is given by the user, the function should print a message indicating that no input was provided.
  
  
  import dialogflow_v2 as dialogflow
  import requests
  
  def run_virtual_assistant():
      project_id = 'project-id'
      session_client = dialogflow.SessionsClient()
      session = session_client.session_path(project_id, 'session-id')
  
      while True:
          text = input('User: ')
          if not text:
              print('No input provided.')
              continue
          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 run_virtual_assistant()  # Output depends on user input, so no specific assertions can be made here.
  
output: def run_virtual_assistant():
      project_id = 'project-id'
      session_client = dialogflow.SessionsClient()
      session = session_client.session_path(project_id, 'session-id')
  
      while True:
          text = input('User: ')
          if not text:
              print('No input provided.')
              continue
          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)