You simply have to create two artists at the initialisation stage, update their coordinates in the update function, and not forget to return a list of updated artists.
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.animation as animation
x = np.arange(130, 190, 1)
y = 97.928 * np.exp(- np.exp(- 0.1416 *( x - 146.1 )))
z = 96.9684 * np.exp(- np.exp(-0.1530*( x - 144.4)))
fig, ax = plt.subplots()
line1, = ax.plot(x, y, color = "r")
line2, = ax.plot(x, z, color = "g")
def update(num, x, y, z, line1, line2):
line1.set_data(x[:num], y[:num])
line2.set_data(x[:num], z[:num])
return [line1,line2]
ani = animation.FuncAnimation(fig, update, len(x), fargs=[x, y, z, line1, line2],
interval=295, blit=True)
ax.set_xlabel('Age (day)')
ax.set_ylabel('EO (%)')
plt.show()
