@abc.abstractmethod<EOL><INDENT>def get_value_query(self):<DEDENT>
return<EOL>
Gets the query for a value.

        :return: the value query
        :rtype: ``osid.configuration.ValueQuery``
        :raise: ``Unimplemented`` -- ``supports_value_query()`` is ``false``

        *compliance: optional -- This method must be implemented if
        ``supports_value_query()`` is ``true``.*