[Python] Python abstract methods for Children, but such that don't prohibit instances of the...

I'm currently using ABC's to ensure that my child classes implement a specific method (or property, in this particular case). I want to make it impossible to create children of Entity without implementing similar_entities:

class Entity(ABC):
@property
@abstractmethod
def similar_entities(self) -> list[str]:
return []

class SubEntity1(Entity):
@property
def similar_entities(self):
return ["a", "b", "c"]

SubEntity1() # Can be instantiated

class SubEntity2(Entity):
pass

SubEntity2() # TypeError


However, I don't actually want to prohibit users from creating instances of the base class Entity itself; creating a "generic" entity is meaningful in this case, and I would like to use the implementation of similar_entities defined on the Entity class itself. I'm only using @abstractmethod to "idiot-check" myself so that I don't accidentally forget to implement this property on my subclasses.

I know full well that the "correct" way to do this would be to create a stub implementation of Entity and use that for generic instances instead:

class GenericEntity(Entity):
@property
def similar_entities(self) -> list[str]:
return super().similar_entities

GenericEntity() # ...


But to me this essentially violates DRY, and since I'm working with such a simple and limited context I'm wondering if there's a way to have my cake and eat it too. Is there any way to massage @abstractmethod to only complain on child-instances? If not, is there some better, more flexible way to establish this contract between my classes? I'm also not opposed to "rolling-my-own" decorator if this is more appropriate in this case.

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