The dictionary types are clearly a powerful tool—you’ll use them all the time. But you might also be tempted to abuse them. Structs in particular might lead you into the darkness because you can associate functions with them in their module definitions. At some point, the old object-orientation neurons still active in the nether regions of your brain might burst into life and you might think, “Hey, this is a bit like a class definition.” And you’d be right. You can write something akin to object-oriented code using structs (or maps) and modules.
This is a bad idea—not because objects are intrinsically bad, but because you’ll be mixing paradigms and diluting the benefits a functional approach gives you.
Stay pure, young coder. Stay pure.
As a way of refocusing you away from the dark side, the next chapter is a mini diversion into the benefits of separating functions and the data they work on. And we disguise it in a discussion of types.