public Lesson geLessonByDayAndHour(string day, int hour)
{
Lesson l = SettingDatabase.GetLessonPractisePractitionerByDayAndHour(this, day, hour);
if (l == null)
{
return(SettingDatabase.GetLessonLabPractitionerByDayAndHour(this, day, hour));
}
else
{
return(l);
}
}