Use render instead of render_to_response.
Use render instead of render_to_response.

Update method to remove context_instance parameter
(https://docs.djangoproject.com/en/1.11/releases/1.8/#dictionary-and-context-instance-arguments-of-rendering-functions)
and use render instead of soon-to-be-deprecated render_to_response
method (https://docs.djangoproject.com/en/1.11/topics/http/shortcuts/#render-to-response).

pydata/symposion,pydata/symposion