How to fix “NotImplementedError” when trying to run Hydrogen in Atom [duplicate]

Answer 1

You can roll back to Python 3.7, or you can edit Tornado to work on 3.8.

Find the tornado / platform / asyncio.py file and add the following code:

import sys

if sys.platform == 'win32':
    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())

From here.