def is_copyright_status_known(self):
return self._payload.is_copyright_status_known()<EOL>
Tests if the copyright status is known.

        return: (boolean) - ``true`` if the copyright status of this
                asset is known, ``false`` otherwise. If ``false,
                is_public_domain(),`` ``can_distribute_verbatim(),
                can_distribute_alterations() and
                can_distribute_compositions()`` may also be ``false``.
        *compliance: mandatory -- This method must be implemented.*