Seems that Generic.__class_getitem__ can't be called automatically after cythonization.

Code sample example.py:

from typing import Generic, TypeVar

T = TypeVar("T")
print(Generic[T])

Cythonization:
cythonize -a -i example.py

The cythonized code fails with TypeError:

>>> import example
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "example.py", line 5, in init example
    print(Generic[T])
TypeError: 'type' object is not subscriptable

Cython 0.29.1
Python 3.7.1