def crl(request, pk):
    """
    returns CRL of a CA
    """
    authenticated = request.user.is_authenticated
    authenticated = authenticated() if callable(authenticated) else authenticated
    if app_settings.CRL_PROTECTED and not authenticated:
        return HttpResponse(_('Forbidden'),
                            status=403,
                            content_type='text/plain')
    ca = crl.ca_model.objects.get(pk=pk)
    return HttpResponse(ca.crl,
                        status=200,
                        content_type='application/x-pem-file')
returns CRL of a CA