@abc.abstractmethod<EOL><INDENT>def get_num_hours_for_day(self, year, month, day):<DEDENT>
return<EOL>
Gets the number of hours for a given day.

        :param year: a year
        :type year: ``integer``
        :param month: a ``DateTime`` month code
        :type month: ``cardinal``
        :param day: a ``DateTime`` day code
        :type day: ``cardinal``
        :return: the number of hours
        :rtype: ``cardinal``
        :raise: ``IllegalState`` -- ``year`` is greater than ``CalendarInfo.getLastYearBeforeCommonEra()`` and less then ``CalendarInfo.getFirstYearInCommonEra()`` , or ``month`` is greater than or equal to
``CalendarInfo.getNumMonthsForYear(year)`` , or ``day`` is greater than or equal to ``CalendarInfo.getDaysInMonth(year, month)``
        :raise: ``OperationFailed`` -- unable to complete request

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