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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def by_summoner_by_champion(self, region, encrypted_summoner_id, champion_id):
 """ 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. """

        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
        )