title: ImportError: cannot import name 'Deque'
body: <p>I'm trying to host my Discord.py bot on Heroku. When my bot starts the following error appears:</p>
  
  <pre><code>2020-01-31T20:49:31.501236+00:00 heroku[worker.1]: State changed from starting to up
  2020-01-31T20:49:32.858327+00:00 heroku[worker.1]: State changed from up to crashed
  2020-01-31T20:49:32.839912+00:00 heroku[worker.1]: Process exited with status 1
  2020-01-31T20:49:32.766672+00:00 app[worker.1]: Traceback (most recent call last):
  2020-01-31T20:49:32.766696+00:00 app[worker.1]:   File "bot.py", line 3, in &lt;module&gt;
  2020-01-31T20:49:32.766815+00:00 app[worker.1]:     import discord
  2020-01-31T20:49:32.766819+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.6/site-packages/discord/__init__.py", line 23, in &lt;module&gt;
  2020-01-31T20:49:32.766952+00:00 app[worker.1]:     from .client import Client
  2020-01-31T20:49:32.766954+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.6/site-packages/discord/client.py", line 35, in &lt;module&gt;
  2020-01-31T20:49:32.767061+00:00 app[worker.1]:     import websockets
  2020-01-31T20:49:32.767062+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.6/site-packages/websockets/__init__.py", line 3, in &lt;module&gt;
  2020-01-31T20:49:32.767164+00:00 app[worker.1]:     from .auth import *
  2020-01-31T20:49:32.767166+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.6/site-packages/websockets/auth.py", line 15, in &lt;module&gt;
  2020-01-31T20:49:32.767263+00:00 app[worker.1]:     from .server import HTTPResponse, WebSocketServerProtocol
  2020-01-31T20:49:32.767265+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.6/site-packages/websockets/server.py", line 49, in &lt;module&gt;
  2020-01-31T20:49:32.767374+00:00 app[worker.1]:     from .protocol import WebSocketCommonProtocol
  2020-01-31T20:49:32.767375+00:00 app[worker.1]:   File "/app/.heroku/python/lib/python3.6/site-packages/websockets/protocol.py", line 18, in &lt;module&gt;
  2020-01-31T20:49:32.767487+00:00 app[worker.1]:     from typing import (
  2020-01-31T20:49:32.767492+00:00 app[worker.1]: ImportError: cannot import name 'Deque'
  </code></pre>
  
  <p>How do I fix this?</p>