docs: def install_default_handler(self, http_error_code):
          """Install a default error handler for `http_error_code`.
  
          The default error handler renders a template named error404.html
          for http_error_code 404.
          """
          logger.debug(
              "Set Default HTTP error handler for status code %d", http_error_code
          )
          handler = partial(self.handle_http_error, http_error_code)
          self.errorhandler(http_error_code)(handler)