(a) Any pupil subject to compulsory full-time education or to compulsory continuation education who is absent from school without valid excuse three full days in one school year or tardy or absent for more than any 30-minute period during the schoolday without a valid excuse on three occasions in one school year, or any combination thereof, is a truant and shall be reported to the attendance supervisor or to the superintendent of the school district.
(b) Notwithstanding subdivision (a), it is the intent of the Legislature that school districts shall not change the method of attendance accounting provided for in existing law and shall not be required to employ period-by-period attendance accounting.