Consistency with variable name

[bruAristimunha]

Based on @GaelVaroquaux's presentation on open-source, we have to say that it is very important to have standardized names and to use exactly the same variable to avoid extra cognitive load.

This image comes from his slides:

I feel like we are not doing this; the case of datasets is more obvious. We sometimes define subjects in some dataset objects, we define subject_list to get data using paradigm, and subjects for the function inside the dataset.

I am in favour of using subjects and putting the type that is a list or doing the cast.

Ideally, we would have some automatic way to do the checking and would be careful with the changes.