public CourseManagementViewModel(
            ICourseEndpoint courseEndpoint,
            ITeacherEndpoint teacherEndpoint,
            IStudentEndpoint studentEndpoint,
            IEventAggregator events)
        {
            this.courseEndpoint  = courseEndpoint;
            this.teacherEndpoint = teacherEndpoint;
            this.studentEndpoint = studentEndpoint;
            eventAggregator      = events;

            LoadCourses();
        }
        public StaffManagementViewModel(
            ITeacherEndpoint teacherEndpoint,
            ICourseEndpoint courseEndpoint,
            IEventAggregator eventAggregator
            )
        {
            this.teacherEndpoint = teacherEndpoint;
            this.courseEndpoint  = courseEndpoint;
            this.eventAggregator = eventAggregator;

            TeachersCoursesControlView   = new TeachersCoursesControlViewModel(courseEndpoint, eventAggregator);
            QualificationsAddControlView = new QualificationsAddControlViewModel(eventAggregator);

            SetUpNewStaffMode();

            LoadStaff();
        }