Check that a submitted comment isn't a duplicate. This might be caused
        by someone posting a comment twice. If it is a dup, silently return the *previous* comment.

def check_for_duplicate_comment(self, new):
        """
        Check that a submitted comment isn't a duplicate. This might be caused
        by someone posting a comment twice. If it is a dup, silently return the *previous* comment.
        """
        possible_duplicates = self.get_comment_model()._default_manager.using(
            self.target_object._state.db
        ).filter(
            content_type=new.content_type,
            object_pk=new.object_pk
        )
        for old in possible_duplicates:
            if old.post_date.date() == new.post_date.date() and old.text == new.text:
                return old

        return new