新手学习Python-可能是基本问题[关闭]

我目前正在学习python ....运行此命令时,出现名称错误-未定义最老的学生...请有人可以解释出了什么问题

class SchoolRegister:
def __init__ (self, name, age, tutor):
    self.name = name
    self.age = age
    self.tutor = tutor

def summary(self):
    print(f'This student is {self.age}, and called {self.name} and are in {self.tutor}\'s tutor group')

def oldest_student(*args):
    return max(args)

pupil1 = SchoolRegister('Vicky', 12, 'Mr Grumpy')
pupil2 = SchoolRegister('Anne', 11, 'Mr Bump')
pupil3 = SchoolRegister('Chris', 12, 'Miss Sunshine')

print(pupil1.summary())
print(pupil2.summary())
print(pupil3.summary())

print(f'The elsest student is {oldest_student((pupil1.age, pupil2.age, pupil3.age))} is years old')       

先感谢您 维琪