Revenu moyen par pays

CLIENTS = [
    {"id": 1, "education": "Master", "revenu": 52000, "pays": "FR", "vins": 300, "viande": 120},
    {"id": 2, "education": "Licence", "revenu": 31000, "pays": "FR", "vins": 80, "viande": 40},
    {"id": 3, "education": "Master", "revenu": 64000, "pays": "ES", "vins": 500, "viande": 200},
    {"id": 4, "education": "Licence", "revenu": 40000, "pays": "FR", "vins": 120, "viande": 60},
    {"id": 5, "education": "Doctorat", "revenu": 82000, "pays": "ES", "vins": 640, "viande": 310},
]

def revenu_par_pays(clients):
    somme, nb = {}, {}
    for c in clients:
        p = c["pays"]
        somme[p] = somme.get(p, 0) + c["revenu"]
        nb[p] = nb.get(p, 0) + ___
    return {p: somme[p] / nb[p] for p in somme}