code: def user_stars_count(self, user_id, extra_query_params={}):
          
          return self.do("GET", "users/{user_id}/stars/count",
                         url_params={"user_id": user_id},
                         query_params=extra_query_params)
docs: client = BacklogClient("your_space_name", "your_api_key")
          client.user_stars_count(5)
          client.user_stars_count(5, {"since": "2017-05-01", "until": "2017-05-31"})