KNN-决策边界可视化

def solve():
    import pandas as pd
    from sklearn.neighbors import KNeighborsClassifier
    from sklearn.model_selection import train_test_split
    df = pd.read_csv(____)
    X = df.iloc[:, :____]
    y = df['____']
    X_train, X_test, y_train, y_test = train_test_split(____)
    knn = KNeighborsClassifier(____)
    knn.fit(____)
    y_pred = knn.predict(____)
    print('____', y_pred[:____].tolist())