def list_genres():
    kwargs = {}
    result = util.callm("%s/%s" % ('artist', 'list_genres'), kwargs)
    return result['response']['genres']
For each (user,item) pair, identify n nearest neighbours that rated this item, 
dataset/ETHPy150Open echonest/pyechonest/pyechonest/artist.py/list_genres--crossover with--dataset/ETHPy150Open ksavenkov/recsys-001/recsys/score.py/user_based_knn