** along the way, I noticed that the reason this notebook hasn't been working since last night is that someone sadly installed a new anaconda python distro today without telling anyone by ELOG. This new distro didn't have all the packages of the previous one. I've updated it with astropy and uncertainties packages.
My bad, sorry!
Yesterday, I was trying to install a package with anaconda's package manager, conda, but it was crashing in some weird way. I wasn't able to fix it, which led me to create a fresh installation.