'Apply any necessary pre-save moderation steps to new
comments.'

def pre_save_moderation(self, sender, comment, request, **kwargs):

    model = comment.content_type.model_class()
    if (model not in self._registry):
        return
    content_object = comment.content_object
    moderation_class = self._registry[model]
    if (not moderation_class.allow(comment, content_object, request)):
        return False
    if moderation_class.moderate(comment, content_object, request):
        comment.is_public = False
