先写出正常运行时的代码：电脑开机后上课 分析电脑会出现的问题，如：蓝屏，冒烟 此时需要自定义两个“蓝屏，冒烟“”自定义异常，封装成对象。 蓝屏后，电脑重启，之后继续上课 电脑冒烟后，出现了老师的问题，不能上课了，可以先做练习，毕老师将问题抛给校长。此时抛出的问题不再是电脑冒烟，而应该是老师不能上课了 问题抛给校长后，校长catch后给出解决方案 效果如图：

class BlueScreenError(Exception):
    def __init__(self, message):
        self.message = message

class SmokeError(Exception):
    def __init__(self, message):
        self.message = message

class TeacherUnableToTeachError(Exception):
    def __init__(self, message):
        self.message = message

class Computer:
    def __init__(self):
        self.is_on = False
    
    def turn_on(self):
        self.is_on = True
        print("电脑已开机")

    def turn_off(self):
        self.is_on = False
        print("电脑已关机")

    def blue_screen(self):
        self.turn_off()
        raise BlueScreenError("电脑出现蓝屏错误")

    def smoke(self):
        self.turn_off()
        raise SmokeError("电脑冒烟了")

class Teacher:
    def __init__(self):
        self.can_teach = True
    
    def teach(self):
        if self.can_teach:
            print("上课中")
        else:
            raise TeacherUnableToTeachError("老师不能上课了")

class Principal:
    def __init__(self):
        pass
    
    def solve_problem(self, problem):
        if isinstance(problem, BlueScreenError):
            print("蓝屏了，电脑已重启")
        elif isinstance(problem, SmokeError):
            print("电脑冒烟了，老师不能上课了，先做练习")
            teacher = Teacher()
            teacher.can_teach = False
            raise TeacherUnableToTeachError("老师不能上课了")

computer = Computer()
try:
    computer.turn_on()
    # 上课中...
    # 电脑出现蓝屏错误
    # computer.blue_screen()
    # 电脑冒烟了
    computer.smoke()
except BlueScreenError as e:
    print(e.message)
    computer.turn_on()
    # 蓝屏了，电脑已重启
except SmokeError as e:
    print(e.message)
    try:
        principal = Principal()
        principal.solve_problem(e)
    except TeacherUnableToTeachError as e:
        print(e.message)