绘制直方图

def solve():
    import matplotlib
    matplotlib.use('Agg')
    import matplotlib.pyplot as plt
    from sklearn.datasets import load_iris
    import numpy as np
    iris = load_iris()
    sepal_length = iris.data[:, 0]
    plt.figure(figsize=(8, 6))
    plt.hist(sepal_length, bins=20)
    plt.title('Sepal Length Distribution')
    plt.xlabel('Sepal Length (cm)')
    plt.ylabel('Frequency')
    plt.tight_layout()
    plt.show()
    print(f'{np.mean(sepal_length):.2f}')