ValueError when using with gzip_page decorator

[tremby]

I'm getting a ValueError: object of type 'NoneType' has no len() when enabling minification and running a view which is decorated with django.views.decorators.gzip.gzip_page.

Traceback (most recent call last):
  File "/usr/local/lib/python3.4/dist-packages/django/core/handlers/base.py", line 131, in get_response
    response = middleware_method(request, response)
  File "/usr/local/lib/python3.4/dist-packages/htmlmin/middleware.py", line 44, in process_response
    parser=parser)
  File "/usr/local/lib/python3.4/dist-packages/htmlmin/minify.py", line 45, in html_minify
    soup = bs4.BeautifulSoup(html_code, parser)
  File "/usr/local/lib/python3.4/dist-packages/bs4/__init__.py", line 192, in __init__
    elif len(markup) <= 256 and (
TypeError: object of type 'NoneType' has no len()

[Diegow3b]

Same here, when im activating GzipMiddleware im getting the same error

[sikmir]

The same problem.