I believe root_locus should only use the axes I send instead of the whole figure. Is this a bug?

import control as ct
import matplotlib.pyplot as plt

fig, axes = plt.subplots(2, 1)

sys = ct.TransferFunction([1, 1, 1], [1, 1, .1, 0])

axes[0].plot([1, 1])
ct.root_locus(sys, ax=axes[1])