code: def get_supported_methods(self, url):
          
          route = self.routes_all.get(url)
          # if methods are None then this logic will prevent an error
          return getattr(route, "methods", None) or frozenset()
docs: Get a list of supported methods for a url and optional host.
  
          :param url: URL string (including host)
          :return: frozenset of supported methods