return null;
return result;
	public String toString() {		String result = "[Dominio.Teacher ";		result += ", teacherNumber=" + getTeacherNumber();		result += ", person=" + getPerson();		result += ", professorShipsExecutionCourses=" + getProfessorShipsExecutionCourses();		result += ", responsibleForExecutionCourses=" + getResponsibleForExecutionCourses();				result += "]";		return null;	}