贝塔分布

def solve():
    import matplotlib.pyplot as plt
    import numpy as np
    from scipy import stats
    x = np.linspace(____, ____, ____)
    plt.figure(figsize=(____, ____))
    params = [(____, ____), (____, ____), (____, ____), (____, ____)]
    for a, b in params:
        pdf = stats.beta.pdf(____)
        plt.plot(____)
    plt.xlabel(____)
    plt.ylabel(____)
    plt.title(____)
    plt.legend()
    plt.grid(____)
    plt.show()