How can I change the font size of ticks of axes object in matplotlib

I have a figure I added subfigure to (inset). I have used: ``` fig = plt.figure() ax = fig.add_subplot(111) subA = fig.add_axes([0.4,0.14,0.2,0.2]) ``` I now want to change the `xtick` font size of the subfigure. I tried some naive approach such as ``` subA.get_xaxis().get_xticks().set_fontsize(10) ``` without any luck. How can I do this then?