matplotlib: AttributeError: ‘AxesSubplot’ object has no attribute ‘add_axes’

You now need to use set_prop_cycle i.e. ax.set_prop_cycle(color=['red', 'green', 'blue'])

Axes.set_color_cycle(clist) was depreciated since, version 1.5.

https://matplotlib.org/3.1.0/api/_as_gen/matplotlib.axes.Axes.set_prop_cycle.html