def info(self, extended=False):
    if (not extended):
        return (self.student_id, self.name, self.grade)
    else:
        return {'student_id': self.student_id, 'fullname': self.name, 'grade': self.grade, 'city': self.city, 'email': self.email, 'gender': self.gender, 'school': self.school}
def info(self, extended=False):
    if (not extended):
        return (self.student_id, self.name, self.grade)
    else:
        return {'student_id': self.student_id, 'fullname': self.name, 'grade': self.grade, 'city': self.city, 'email': self.email, 'gender': self.gender, 'school': self.school}