@abc.abstractmethod<EOL><INDENT>def get_next_calendar_node(self):<DEDENT>
return<EOL>
Gets the next ``CalendarNode`` in this list.

        :return: the next ``CalendarNode`` in this list. The ``has_next()`` method should be used to test that a next
        ``CalendarNode`` is available before calling this method.
        :rtype: ``osid.calendaring.CalendarNode``
        :raise: ``IllegalState`` -- no more elements available in this list
        :raise: ``OperationFailed`` -- unable to complete request

        *compliance: mandatory -- This method must be implemented.*