namedtuple broken Python 3.9.0

README.md

In Python <= 3.8, if you run:

from collections import namedtuple
MyClass = namedtuple("MyClass", "")
m = MyClass()
print(m.__class__['__name__'])
print(type(m.__class__['__name__']))

It will raise TypeError in:

print(m.__class__['__name__'])

In Python 3.9 it prints:

types.GenericAlias