模型评估：交叉验证

def solve():
    from sklearn.datasets import load_iris
    from sklearn.model_selection import cross_val_score
    from sklearn.ensemble import RandomForestClassifier
    import numpy as np
    iris = load_iris()
    model = RandomForestClassifier(____)
    scores = cross_val_score(____)
    print(____)
    print(____)
    print(____)