I keep getting NotImplementedError error when starting django server [duplicate] - django

Question

This question already has answers here:
Jupyter Notebook with Python 3.8 - NotImplementedError
(4 answers)
Closed 3 years ago.
Below is a full trace of the error. Please let me know what could fix this issue:
(env) C:\Users\LENOVO\Desktop\SD\backend>python manage.py runserver
Watching for file changes with StatReloader
Exception in thread django-main-thread:
Traceback (most recent call last):
File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python38-32\lib\threading.py", line 932, in _bootstrap_inner
self.run()
File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python38-32\lib\threading.py", line 870, in run
self._target(*self._args, **self._kwargs)
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\utils\autoreload.py", line 54, in wrapper
fn(*args, **kwargs)
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\core\management\commands\runserver.py", line 109, in inner_run
autoreload.raise_last_exception()
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\utils\autoreload.py", line 77, in raise_last_exception
raise _exception[1]
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\core\management\__init__.py", line 337, in execute
autoreload.check_errors(django.setup)()
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\utils\autoreload.py", line 54, in wrapper
fn(*args, **kwargs)
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\__init__.py", line 24, in setup
apps.populate(settings.INSTALLED_APPS)
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\apps\registry.py", line 91, in populate
app_config = AppConfig.create(entry)
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\django\apps\config.py", line 116, in create
mod = import_module(mod_path)
File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python38-32\lib\importlib\__init__.py", line 127, in import_module
return _bootstrap._gcd_import(name[level:], package, level)
File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
File "<frozen importlib._bootstrap>", line 991, in _find_and_load
File "<frozen importlib._bootstrap>", line 975, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 671, in _load_unlocked
File "<frozen importlib._bootstrap_external>", line 783, in exec_module
File "<frozen importlib._bootstrap>", line 219, in _call_with_frames_removed
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\channels\apps.py", line 6, in <module>
import daphne.server
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\daphne\server.py", line 18, in <module>
asyncioreactor.install()
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\twisted\internet\asyncioreactor.py", line 320, in install
reactor = AsyncioSelectorReactor(eventloop)
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\twisted\internet\asyncioreactor.py", line 69, in __init__
super().__init__()
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\twisted\internet\base.py", line 571, in __init__
self.installWaker()
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\twisted\internet\posixbase.py", line 286, in installWaker
self.addReader(self.waker)
File "C:\Users\LENOVO\Desktop\SD\backend\env\lib\site-packages\twisted\internet\asyncioreactor.py", line 151, in addReader
self._asyncioEventloop.add_reader(fd, callWithLogger, reader,
File "C:\Users\LENOVO\AppData\Local\Programs\Python\Python38-32\lib\asyncio\events.py", line 501, in add_reader
raise NotImplementedError
NotImplementedError

Answer 1

Twisted is not supported on 3.8 on Windows, so one solution would be to switch back to Python 3.7.
I got it working on Python 3.8 by replacing the following lines in packages/twisted/internet/asyncioreactor.py
from twisted.internet.interfaces import IReactorFDSet
try:
from asyncio import get_event_loop
except ImportError:
raise ImportError("Requires asyncio.")
# As per ImportError above, this module is never imported on python 2, but
with
from twisted.internet.interfaces import IReactorFDSet
import sys
try:
from asyncio import get_event_loop, set_event_loop_policy, WindowsSelectorEventLoopPolicy
except ImportError:
raise ImportError("Requires asyncio.")
if sys.platform == 'win32':
set_event_loop_policy(WindowsSelectorEventLoopPolicy())
# As per ImportError above, this module is never imported on python 2, but
From the similar problem faced by Tornado here.