@abc.abstractmethod<EOL><INDENT>def add_blackout(self, recurring_event_id, from_, to):<DEDENT>
pass<EOL>
Adds a blackout to the given recurring event that blocks events in the series.

        :param recurring_event_id: a recurring event ``Id``
        :type recurring_event_id: ``osid.id.Id``
        :param from: start date inclusive
        :type from: ``osid.calendaring.DateTime``
        :param to: end date inclusive
        :type to: ``osid.calendaring.DateTime``
        :raise: ``InvalidArgument`` -- ``from`` is greater than ``to``
        :raise: ``NotFound`` -- ``recurring_event_id`` is not found
        :raise: ``NullArgument`` -- ``recurring_event_id, from`` or ``to`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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