code: def _add_url_route(self, endpoint, rule, view_func, method):
          
          if self.api_prefix:
              rule = self.api_prefix + rule
  
          if self.endpoint_prefix:
              endpoint = self.endpoint_prefix + endpoint
  
          self.app.add_url_rule(
              rule,
              endpoint,
              self._apply_auth(view_func),
              methods=[method]
          )
docs: Add a Flask route.
          :param str endpoint: The endpoint name.
          :param str rule: The endpoint url.
          :param view_func: The endpoint func
          :param str method: The http method.