how to show tick labels on top of matplotlib plot?

In matplotlib what is the way to have tick labels both at the bottom and in the top x axis? I have searched a lot and still can’t find how to do it.

Answer

Sorry, I lied in the comments. You can do this easily (but it seems to be badly documented)

fig, ax = plt.subplots(1, 1)
ax.xaxis.set_tick_params(labeltop='on')