code: def is_subscribed(self, login, repo):
          
          json = False
          if login and repo:
              url = self._build_url('user', 'subscriptions', login, repo)
              json = self._boolean(self._get(url), 204, 404)
          return json
docs: Check if the authenticated user is subscribed to login/repo.
  
          :param str login: (required), owner of repository
          :param str repo: (required), name of repository
          :returns: bool