Where can I find a reference to python 3.7 commands?

[ichabod801]

Neither plot or array are defined in Python 3.7. If you're using Spyder, it claims to offer 'built-in integration' with many scientific packages. My guess is those packages are loading by default, maybe numpy (array) and matplotlib (plot).

I would try help(plot). That should give you some information on the function, perhaps which package they are from.