Upgrade to django v1.9 causes "RemovedInDjango110Warning: django.conf.urls.patterns() is deprecated"

django_markdown/urls.py:8: RemovedInDjango110Warning: django.conf.urls.patterns() is deprecated and will be removed in Django 1.10. Update your urlpatterns to be a list of django.conf.urls.url() instances instead.
'', url('preview/$', preview, name='django_markdown_preview'))
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Start with django_markdown/urls.py at line 8 and inspect how urlpatterns currently uses django.conf.urls.patterns(). Verify the URL configuration under Django 1.9, then confirm that the deprecated warning is gone and the preview URL still resolves correctly.

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