@abc.abstractmethod<EOL><INDENT>def get_number_of_events_in_date_range(self, recurring_event_id, from_, to):<DEDENT>
return<EOL>
Gets the number of events in the recurring series between the given dates inclusive.

        :param recurring_event_id: ``Id`` of the recurring ``Event``
        :type recurring_event_id: ``osid.id.Id``
        :param from: start date
        :type from: ``osid.calendaring.DateTime``
        :param to: end date
        :type to: ``osid.calendaring.DateTime``
        :return: the number of meeting times
        :rtype: ``cardinal``
        :raise: ``InvalidArgument`` -- ``to`` is less than ``from``
        :raise: ``NotFound`` -- ``recurring_event_id was`` not found
        :raise: ``NullArgument`` -- ``recurring_event_id`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

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