code: def url_for(endpoint_or_url_or_config_key: str,
              _anchor: Optional[str] = None,
              _cls: Optional[Union[object, type]] = None,
              _external: Optional[bool] = False,
              _external_host: Optional[str] = None,
              _method: Optional[str] = None,
              _scheme: Optional[str] = None,
              **values,
              ) -> Union[str, None]:
      what = endpoint_or_url_or_config_key
      if what and what.isupper():
          what = current_app.config.get(what)
      if isinstance(what, LocalProxy):
          what = what._get_current_object()
      if not what or '/' in what:
          return what
      flask_url_for_kwargs = dict(_anchor=_anchor, _external=_external,
                                  _external_host=_external_host, _method=_method,
                                  _scheme=_scheme, **values)
      if _cls and '.' not in what:
          controller_routes = getattr(_cls, CONTROLLER_ROUTES_ATTR)
          method_routes = controller_routes.get(what)
          try:
              return _url_for(method_routes[0].endpoint, **flask_url_for_kwargs)
          except (
              BuildError,
              IndexError,
              TypeError,
          ):
              pass
      return _url_for(what, **flask_url_for_kwargs)