Registry

Layer 4: Extend Framework

saealib.register	Register a class or function under name (default cls.__name__).
saealib.registry.build	Recursively construct an object from a spec; non-spec values pass through.
saealib.registry.get	Resolve name to a class/function via the registry, or a dotted path.
saealib.registry.to_spec	Recursively serialize obj into a spec (the reverse of build()).