def METHOD_NAME(
    self, force_insert=False, force_update=False, using=None, update_fields=None
):
    try:
        assert (self.parent_article is None) != (self.parent_comment is None)
    except AssertionError:
        raise IntegrityError(
            "self.parent_article and self.parent_comment should exist exclusively."
        )
    try:
        assert not self.parent_comment or not self.parent_comment.parent_comment
    except AssertionError:
        raise IntegrityError("comment of comment of comment is not allowed")
    try:
        assert self.content is not None or self.attachment is not None
    except AssertionError:
        raise IntegrityError("self.content and self.attachment should exist.")
    self.content = sanitize(self.content)
    super(Comment, self).METHOD_NAME(
        force_insert=force_insert,
        force_update=force_update,
        using=using,
        update_fields=update_fields,
    )