Good luck introspecting a given python object and ascertaining "this class only stores data". It's literally impossible given the dynamicism of python. The con

Good luck introspecting a given python object and ascertaining "this class only stores data". It's literally impossible given the dynamicism of python. The consequences are exposing state that you don't necessarily want to expose, missed opportunities for optimization (lose fine-grained memory/performance tradeoff ability), imply something is serializable when it isn't, collisions with metaclasses/inheritance weirdness.