def get_catalog_session(self):
raise Unimplemented()<EOL>
Gets the cataloging session for retrieving mappings to catalogs.

        return: (osid.cataloging.CatalogSession) - a ``CatalogSession``
        raise:  OperationFailed - unable to complete request
        raise:  Unimplemented - ``supports_catalog()`` is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_catalog()`` is ``true``.*