The goal of a ABC metaclass is that can assist you detect gaps within your implementation; it never was intended to enforce the kinds with the attributes. MaartenMaarten 23k33 gold badges5151 silver badges6969 bronze badges Insert a comment You'll be able to simply get this member with num = foo.num. https://emperiumgurugram.in/emperium-premio-sector-37c-gurgaon-urban-elegance-with-seamless-connectivity/