交叉验证-K折

def solve():
    import pandas as pd
    import numpy as np
    from sklearn.neighbors import KNeighborsClassifier
    from sklearn.model_selection import cross_val_score
    df = pd.read_csv(____)
    X = df.drop(____)
    y = df['____']
    knn = KNeighborsClassifier(____)
    scores = cross_val_score(____)
    print('____', scores.round(____))
    print('____', round(scores.mean(), ____))