text: Title: Switch between search engines
  Body: I was looking at the search_on_web method, and although you can set the search engine it uses, there's no way you can do it from the SearchInternetNode class. Are you guys planning to allow it using the node_config the same way as the max_results ?
  
  answer = search_on_web(query=search_query, max_results=self.max_results)