So I'm using a simple, deliberately not correct version of "functional" because a lot of people don't know the difference. I don't like it when people break ou

So I'm using a simple, deliberately not correct version of "functional" because a lot of people don't know the difference. I don't like it when people break out their monocle and pipe and complain about this or that being true functional :-). I really do just mean "procedural functions + return by value instead of mutation" here. It is completely normal to have a python script that is just ordinary functions, without state being enclosed in a class and accessed via `self`. This "My First Program" behavior scales extremely well, both from a parallelism perspective, as well from a complexity perspective. OO features can be applied iteratively on top of that. With Ruby--syntax aside--it is just very rare to see people only write functions or private_class_methods. The "Everything is a Class" mantra is very strong, and there's lots of rich behavior in Ruby attached onto what would be considered primitives or basic structs in Python. With data science specifically, this natural way of pushing simple procedures, primitives, structs from Python down into C has lots of performance benefits. Because those functions are "flat", you don't have to traverse the call stack routinely and lose performance there.