def get_item_query(self):
raise errors.Unimplemented()<EOL>
Gets the query for an item.

        Multiple retrievals produce a nested ``OR`` term.

        return: (osid.assessment.ItemQuery) - the item query
        raise:  Unimplemented - ``supports_item_query()`` is ``false``
        *compliance: optional -- This method must be implemented if
        ``supports_item_query()`` is ``true``.*