Contour plot for net CAGR of normally distributed returns

import matplotlib
matplotlib.use('TkAgg')

from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt

def norm_data():
    '''Return normalized data'''
    cagrs = []
    mus = range(0, 100)
    sigmas = [x*0.5 for x in range(0, 200)]
    for sigma in tqdm(sigmas):
        cagr = []
        for mu in mus:
            cagr.append(normal_returns(mu, sigma))
        cagrs.append(cagr)
    return (mus, sigmas, cagrs)

norm_x, norm_y, norm_z = norm_data()

fig = plt.figure()
cp = plt.contour(norm_x, norm_y, norm_z)
plt.clabel(cp, inline=True, fontsize=10)
plt.title('Net CAGR')
plt.xlabel('Mean Returns')
plt.ylabel('Deviation')
plt.show()