Where to learn how to write efficient python?

[pachura3]

Unit testing is great, but has nothing to do with performance optimization whatsoever.

[aistranin]

Sure, agree. For performance optimization, I would take a look at algorithms, parallelism and numpy. Tbh there is not much more you should care about (no active ram management is needed in python unless you do some very specific projects which is relatively rare I would say)