This is temporary, again. The goal was to compare both results. 

However, we need a way to show new users how to use the "low-level" API. What we did previously with plot_regions_covariance.py was to add another script, containing the "advanced" version. In the long run this is not a good idea, since it will basically mean duplicating every example file. 

So the question is: where do we put "advanced" examples?