public async Task AddTeacherAsync(TeacherViewModel model) { var teacher = await _teacherRepo.GetTeacherByIdAsync(model.TeacherId); if (teacher != null) { throw new Exception("Nauczyciel już istnieje w bazie!"); } else { teacher = new Teacher(Guid.NewGuid(), Guid.NewGuid(), model.FirstName, model.LastName, model.Languages, model.City, model.Address, model.ZipCode); await _teacherRepo.AddTeacherAsync(teacher); } }