@abc.abstractmethod<EOL><INDENT>def get_calendar_admin_session(self):<DEDENT>
return<EOL>
Gets the OsidSession associated with the calendar administration service.

        :return: a ``CalendarAdminSession``
        :rtype: ``osid.calendaring.CalendarAdminSession``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``Unimplemented`` -- ``supports_calendar_admin() is false``

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