import matplotlib.pyplot as plt
import numpy as np
import scipy.stats as st
import arviz as az
plt.style.use('arviz-darkgrid')
x = np.linspace(-6, 9, 200)
mus = [0., -2., 0., -3.]
sigmas = [1., 1., 3., 1.]
nus = [1., 1., 1., 4.]
for mu, sigma, nu in zip(mus, sigmas, nus):
    pdf = st.exponnorm.pdf(x, nu/sigma, loc=mu, scale=sigma)
    plt.plot(x, pdf, label=r'$\mu$ = {}, $\sigma$ = {}, $\nu$ = {}'.format(mu, sigma, nu))
plt.xlabel('x', fontsize=12)
plt.ylabel('f(x)', fontsize=12)
plt.legend(loc=1)
plt.show()