def defaults(self):
        """Return default metadata."""
        return dict(
            access_right='open',
            description=self.description,
            license='other-open',
            publication_date=self.release['published_at'][:10],
            related_identifiers=list(self.related_identifiers),
            version=self.version,
            title=self.title,
            upload_type='software',
        )
Return default metadata.