模型评估：学习曲线

def solve():
    from sklearn.datasets import load_iris
    from sklearn.model_selection import learning_curve
    from sklearn.ensemble import RandomForestClassifier
    import matplotlib.pyplot as plt
    import numpy as np
    iris = load_iris()
    model = RandomForestClassifier(____)
    train_sizes, train_scores, test_scores = learning_curve(____)
    train_mean = np.mean(____)
    train_std = np.std(____)
    test_mean = np.mean(____)
    test_std = np.std(____)
    plt.figure(figsize=(____, ____))
    plt.plot(____)
    plt.fill_between(____)
    plt.plot(____)
    plt.fill_between(____)
    plt.xlabel(____)
    plt.ylabel(____)
    plt.title(____)
    plt.legend()
    plt.grid(____)
    plt.show()