[Python] Subclass of Generic fails with AttributeError: object has no attribute...

I have a setup like the following

from typing import Generic, TypeVar
T = TypeVar("T")

class ThirdParty:
def __init_subclass__(cls):
... # does not call super()

class Mine(ThirdParty, Generic[T]):
...

class Sub(Mine[int]):
...


However it fails with the following

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/dsperber/master/repos/SYMPOL/rllib_port/core/stated_flax_model.py", line 27, in <module>
class Sub(Mine[ModelType]):
File "/home/xxxx/miniconda3/envs/python3.10/lib/python3.10/typing.py", line 309, in inner
return cached(*args, **kwds)
File "/home/xxxx/miniconda3/envs/python3.10/lib/python3.10/typing.py", line 1342, in __class_getitem__
if any(isinstance(t, ParamSpec) for t in cls.__parameters__):

AttributeError: type object 'Mine' has no attribute '__parameters__'


I figured out that this is because ThirdParty has a __init_subclass__ function but it does not call super().__init_subclass__, hence Generic.__init_subclass__ is not called. Is there a way around this? Adding __init_subclass__ to Mine does not work or the following fails as well:

def __init_subclass__(cls):
Generic.__init_subclass__(cls)
# TypeError: Generic.__init_subclass__() takes 1 positional argument but 2 were given

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