Eaiser and better to just pass your function an Axes
:
def my_plot_1(x, y, ax):
ax.plot(x, y)
def my_plot_2(x, y, ax):
ax.plot(x, y)
fig, axs = plt.subplots(ncols=2, nrows=1)
# pass the Axes you created above
my_plot_1(x, y, axs[0])
my_plot_2(x, y, axs[1])