code: def by_summoner_by_champion(self, region, encrypted_summoner_id, champion_id):
          
          url, query = ChampionMasteryApiV4Urls.by_summoner_by_champion(
              region=region,
              encrypted_summoner_id=encrypted_summoner_id,
              champion_id=champion_id,
          )
          return self._raw_request(
              self.by_summoner_by_champion.__name__, region, url, query
          )
docs: Get a champion mastery by player ID and champion ID.
  
          :param string                           region: the region to execute this request on
          :param string encrypted_summoner_id:    Summoner ID associated with the player
          :param long champion_id:                Champion ID to retrieve Champion Mastery for
  
          :returns: ChampionMasteryDTO: This object contains single Champion Mastery information for
                                        player and champion combination.