@abc.abstractmethod<EOL><INDENT>def get_installation_query(self):<DEDENT>
return<EOL>
Gets the query for an installation.

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

        :return: the installation query
        :rtype: ``osid.installation.InstallationQuery``
        :raise: ``Unimplemented`` -- ``supports_installation_query()`` is ``false``

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