@Override
protected void assemble(Fields fields) {
if (acAcademicYearsField == null) {
acAcademicYearsField = new AcademicYearsDurationField(this);
acAcademicYear = new AcademicYearDateTimeField(this);
acAcademicTrimester = new AcademicTrimesterDateTimeField(this);
acAcademicTrimestersField = new AcademicTrimesterDurationField(this);
acAcademicSemester = new AcademicSemesterDateTimeField(this);