mwe for saving an animation with pillow

pillowriter.py

import matplotlib.pyplot as plt
from matplotlib.animation import FuncAnimation

numHeatMaps = 2
measurements = [[(i + 1, j + 1, k * 100 + i * 10 + j) for i in range(5) for j in range(5)] for k in range(numHeatMaps)]

fig, ax = plt.subplots()
im = ax.imshow(measurements[0])

def update(i):
    im.set_data(measurements[i])

ani = FuncAnimation(fig, update, frames=len(measurements))
ani.save("test.gif", writer="pillow")

plt.show()