Crash on registration renew page

One-sentence description

Crash on registration renew page

Current behaviour

File "/usr/local/lib/python3.5/site-packages/django/core/handlers/exception.py" in inner
 35.             response = get_response(request)

File "/usr/local/lib/python3.5/site-packages/django/core/handlers/base.py" in _get_response
 128.                 response = self.process_exception_by_middleware(e, request)

File "/usr/local/lib/python3.5/site-packages/django/core/handlers/base.py" in _get_response
 126.                 response = wrapped_callback(request, *callback_args, **callback_kwargs)

File "/usr/local/lib/python3.5/site-packages/django/views/generic/base.py" in view
 69.             return self.dispatch(request, *args, **kwargs)

File "/usr/local/lib/python3.5/site-packages/django/utils/decorators.py" in _wrapper
 62.             return bound_func(*args, **kwargs)

File "/usr/local/lib/python3.5/site-packages/django/contrib/auth/decorators.py" in _wrapped_view
 21.                 return view_func(request, *args, **kwargs)

File "/usr/local/lib/python3.5/site-packages/django/utils/decorators.py" in bound_func
 58.                 return func.__get__(self, type(self))(*args2, **kwargs2)

File "/usr/local/lib/python3.5/site-packages/django/views/generic/base.py" in dispatch
 89.         return handler(request, *args, **kwargs)

File "/usr/local/lib/python3.5/site-packages/django/views/generic/edit.py" in get
 133.         return self.render_to_response(self.get_context_data())

File "./registrations/views.py" in get_context_data
 143.             c[1] for c in Membership.MEMBERSHIP_TYPES

File "./registrations/views.py" in <listcomp>
 144.             if c[0] == context['membership'].type

Exception Type: AttributeError at /registration/renew/
Exception Value: 'NoneType' object has no attribute 'type'
Request information:
USER: azijlstra

Expected behaviour

No crash

Steps to reproduce

Unknown