模型评估：验证曲线

def solve():
    from sklearn.datasets import load_iris
    from sklearn.model_selection import validation_curve
    from sklearn.ensemble import RandomForestClassifier
    import matplotlib.pyplot as plt
    import numpy as np
    iris = load_iris()
    param_range = [____, ____, ____, ____, ____]
    train_scores, test_scores = validation_curve(RandomForestClassifier(____), iris.data, iris.target, param_name='____', param_range=param_range, cv=____)
    train_mean = np.mean(____)
    test_mean = np.mean(____)
    plt.figure(figsize=(____, ____))
    plt.plot(____)
    plt.plot(____)
    plt.xlabel(____)
    plt.ylabel(____)
    plt.title(____)
    plt.legend()
    plt.grid(____)
    plt.show()