想问问下面这个图用python怎么画

求问图中的黄色线段用python怎么画
直线代表几个点的拟合回归线，黄色线段表示的是实际值与拟合值之间的差值，主要是不知道黄色线段怎么画

import matplotlib.pyplot as plt
import numpy as np


def Laplacian_Prior(x, u, b):
    
    return 1.0/(2*b)*np.exp(-abs(x - u)/b)

if __name__ == "__main__":
    
    x = np.arange(-10, 10, 0.01)
    y_1 = Laplacian_Prior(x, 0, 1)
    y_2 = Laplacian_Prior(x, 0, 2)
    y_3 = Laplacian_Prior(x, 0, 4)
    y_4 = Laplacian_Prior(x, -5, 4)
    plt.plot(x, y_1, "r-")
    plt.plot(x, y_2, "k-")
    plt.plot(x, y_3, "b-")
    plt.plot(x, y_4, "g-")
    plt.vlines(0, 0, 0.5, colors = "c", linestyles = "dashed")