Module has no attribute "__cached__"

Bug Report

Modules have a __cached__ attribute which points at the pyc location. mypy does not understand this attribute

Here's an example bit of code:

import copyreg
print(copyreg.__cached__)

OUTPUT = '''\
/usr/lib/python3.8/__pycache__/copyreg.cpython-38.pyc
'''

To Reproduce

(Write your steps here:)

1. Run mypy against the sample file

Expected Behavior

I expect no errors

Actual Behavior

$ mypy t.py
t.py:2: error: Module has no attribute "__cached__"
Found 1 error in 1 file (checked 1 source file)

Your Environment

• sys.version: '3.8.5 (default, Jul 28 2020, 12:59:40) \n[GCC 9.3.0]'
• os.name: 'posix'
• sys.platform: 'linux'
• platform.system(): 'Linux'
• platform.python_implementation(): 'CPython'
• sys.implementation.name: 'cpython'
• sysconfig.get_platform(): 'linux-x86_64'

$ mypy --version
mypy 0.790

Inizia creando o eseguendo il file di esempio t.py con mypy 0.790 e conferma l’errore segnalato per copyreg.cached. Traccia il modo in cui mypy rappresenta gli attributi dei moduli, quindi aggiungi la copertura per questo caso e verifica che mypy non segnali errori per l’esempio.