Getting "NotImplementedError" from Mkdocs serve command [duplicate]

Question

I am setting up a documentation using mkdocs but I am getting "NotImplementedError" when runing the "mkdocs serve" command

Note that I am working on windows 10 and installed the Python 3.8.0a3 version

INFO    -  Building documentation... 
INFO    -  Cleaning site directory 
[I 190419 16:50:46 server:298] Serving on http://127.0.0.1:8000
Traceback (most recent call last):
  File "c:\python38\lib\runpy.py", line 192, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "c:\python38\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\Python38\Scripts\mkdocs.exe\__main__.py", line 9, in <module>
  File "c:\python38\lib\site-packages\click\core.py", line 764, in __call__
    return self.main(*args, **kwargs)
  File "c:\python38\lib\site-packages\click\core.py", line 717, in main
    rv = self.invoke(ctx)
  File "c:\python38\lib\site-packages\click\core.py", line 1137, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "c:\python38\lib\site-packages\click\core.py", line 956, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "c:\python38\lib\site-packages\click\core.py", line 555, in invoke
    return callback(*args, **kwargs)
  File "c:\python38\lib\site-packages\mkdocs\__main__.py", line 128, in serve_command
    serve.serve(
  File "c:\python38\lib\site-packages\mkdocs\commands\serve.py", line 124, in serve
    _livereload(host, port, config, builder, site_dir)
  File "c:\python38\lib\site-packages\mkdocs\commands\serve.py", line 58, in _livereload
    server.serve(root=site_dir, host=host, port=port, restart_delay=0)
  File "c:\python38\lib\site-packages\livereload\server.py", line 300, in serve
    self.application(
  File "c:\python38\lib\site-packages\livereload\server.py", line 255, in application
    app.listen(port, address=host)
  File "c:\python38\lib\site-packages\tornado\web.py", line 2112, in listen
    server.listen(port, address)
  File "c:\python38\lib\site-packages\tornado\tcpserver.py", line 152, in listen
    self.add_sockets(sockets)
  File "c:\python38\lib\site-packages\tornado\tcpserver.py", line 165, in add_sockets
    self._handlers[sock.fileno()] = add_accept_handler(
  File "c:\python38\lib\site-packages\tornado\netutil.py", line 279, in add_accept_handler
    io_loop.add_handler(sock, accept_handler, IOLoop.READ)
  File "c:\python38\lib\site-packages\tornado\platform\asyncio.py", line 99, in add_handler
    self.asyncio_loop.add_reader(fd, self._handle_events, fd, IOLoop.READ)
  File "c:\python38\lib\asyncio\events.py", line 498, in add_reader
    raise NotImplementedError
NotImplementedError

I would like to get where the error come from and fix it

Answer 1

It seems like mkdocs does not the support the latest version of python which is 3.8.0a3. In my case I fixed it by downgrading to 3.7