```
Exception in thread django-main-thread:
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/django/template/utils.py", line 66, in __getitem__
    return self._engines[alias]
KeyError: 'django'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
...
  File "/usr/local/lib/python3.6/site-packages/markdown/util.py", line 88, in <module>
    INSTALLED_EXTENSIONS = metadata.entry_points(group='markdown.extensions')
TypeError: entry_points() got an unexpected keyword argument 'group'
```

(same error as last commit, 0727e32)