I'd say the basics are stuff that are universal throughout most languages. So yeah variables and functions are a must, and that includes things like parameters too.

I'd also make sure you understand the difference between iteration and selection, as well as how to use them. Iteration includes loops such as while and for, there's more but some are language dependent, while and for are the ones that you'll need the most.

For selection make sure you understand how if, else and else if statements work and the operators that are used alongside them. It could also be useful to look into case/switch but I don't believe Python has it.

There's a lot more stuff but it's hard to define what is basic because it's just based on opinion. I'd consider you past a basic level when you feel comfortable writing your own programs without just following what someone on a guide is doing. If you go through the majority of the course on Codecademy you're guaranteed to come out at the end with solid knowledge of the language.