def get_version(self, version_id=None):
        """Return specific version ``ObjectVersion`` instance or HEAD.

        :param version_id: Version ID of the object.
        :returns: :class:`~invenio_files_rest.models.ObjectVersion` instance or
            HEAD of the stored object.
        """
        return ObjectVersion.get(bucket=self.obj.bucket, key=self.obj.key,
                                 version_id=version_id)
Return specific version ``ObjectVersion`` instance or HEAD.

        :param version_id: Version ID of the object.
        :returns: :class:`~invenio_files_rest.models.ObjectVersion` instance or
            HEAD of the stored object.