title: AttributeError: type object 'Callable' has no attribute '_abc_registry'
body: <p>When I open my jupyter notebook I get errors.</p>
  
  <p>I use google for help, but I can't find an answer. </p>
  
  <p>I'm on macOS mojave and using python 3.7.2.I reinstalled my Jupiter notebook but no change.</p>
  
  <p>When I input jupyter notebook. It show me these</p>
  
  <pre class="lang-none prettyprint-override"><code>Last login: Wed Apr 24 23:06:17
  miracleleon@MiracledeMBP  ~  jupyter notebook
  Traceback (most recent call last):
  File "/usr/local/bin/jupyter-notebook", line 6, in 
  from notebook.notebookapp import main
  File "/usr/local/lib/python3.7/site-packages/notebook/init.py", line 25, in 
  from .nbextensions import install_nbextension
  File "/usr/local/lib/python3.7/site-packages/notebook/nbextensions.py", line 610, in 
  from .extensions import (
  File "/usr/local/lib/python3.7/site-packages/notebook/extensions.py", line 8, in 
  from tornado.log import LogFormatter
  File "/usr/local/lib/python3.7/site-packages/tornado/log.py", line 34, in 
  from tornado.escape import _unicode
  File "/usr/local/lib/python3.7/site-packages/tornado/escape.py", line 27, in 
  from tornado.util import unicode_type
  File "/usr/local/lib/python3.7/site-packages/tornado/util.py", line 18, in 
  import typing
  File "/usr/local/lib/python3.7/site-packages/typing.py", line 1356, in 
  class Callable(extra=collections_abc.Callable, metaclass=CallableMeta):
  File "/usr/local/lib/python3.7/site-packages/typing.py", line 1004, in new
  self._abc_registry = extra._abc_registry
  AttributeError: type object 'Callable' has no attribute '_abc_registry'
  </code></pre>