def get_champion_mastery(summoner_id, champion_id):
    region = cassiopeia.type.core.common.Region(cassiopeia.dto.requests.region)
    platform = cassiopeia.type.core.common.Platform[region.name]

    # Get JSON response
    request = "https://{server}.api.pvp.net/championmastery/location/{platform}/player/{summonerId}/champion/{championId}".format(server=cassiopeia.dto.requests.region, platform=platform.value, summonerId=summoner_id, championId=champion_id)
    return cassiopeia.type.dto.championmastery.ChampionMastery(cassiopeia.dto.requests.get(request, include_base=False))
https://developer.riotgames.com/api/methods#!/1034/3545
dataset/ETHPy150Open meraki-analytics/cassiopeia/cassiopeia/dto/championmasteryapi.py/get_champion_mastery