public List <Teacher> GetAllTeachersManager()
 {
     return(_teacherGateway.GetAllTeachers());
 }
 public List <Teacher> GetAllTeachers()
 {
     return(aTeacherGateway.GetAllTeachers());
 }
 public List <Teacher> GetAllTeachers(int departmentId)
 {
     aTeacherGateway = new TeacherGateway();
     return(aTeacherGateway.GetAllTeachers(departmentId));
 }