Agreed. I'd like CPython to offer the possibility to opt in semantics that are more amenable to optimizations, similar to what Cider is enabling with their opt-

Agreed. I'd like CPython to offer the possibility to opt in semantics that are more amenable to optimizations, similar to what Cider is enabling with their opt-in strict modules and static classes: https://github.com/facebookincubator/cinder https://github.com/facebookincubator/cinder.