'Check permissions as normal, but also check that we can access the
parent extension.'

def check_permissions(self, request):

    super(ExtensionVersionViewSet, self).check_permissions(request)
    extension = self.get_extension_object()
    if (extension.disabled and (self.request.method not in SAFE_METHODS)):
        raise PermissionDenied(_(u'Modifying    or    submitting    versions    is    forbidden    for    disabled    Add-ons.'))
    super(ExtensionVersionViewSet, self).check_object_permissions(request, extension)
