docs: def get_confidence(self, url=None, article_id=None):
          """
          Send a GET request to the `confidence` endpoint of the Parser API.
  
          Note that either the `url` or `article_id` param should be passed.
  
          :param url (optional): The url of an article whose content is wanted.
          :param article_id (optional): The id of an article in the Readability
              system whose content is wanted.
          """
          query_params = {}
          if url is not None:
              query_params['url'] = url
          if article_id is not None:
              query_params['article_id'] = article_id
          url = self._generate_url('confidence', query_params=query_params)
          return self.get(url)