tryexception的问题

Question

问题在output注释里

class MyZeroDivisionError(ZeroDivisionError):    
    pass


def do_the_division(mine):
    if mine:
        raise MyZeroDivisionError("some worse news")
    else:        
        raise ZeroDivisionError("some bad news")


for mode in [False, True]:
    try:
        do_the_division(mode)
    except ZeroDivisionError:
        print('Division by zero')

for mode in [False, True]:
    try:
        do_the_division(mode)
    except MyZeroDivisionError:
        print('My division by zero')
    except ZeroDivisionError:
        print('Original division by zero')

ouput:
Division by zero
Division by zero #当mode为True的时候，为什么还是print “Division by zero”
Original division by zero
My division by zero

Answer 1

class MyZeroDivisionError(ZeroDivisionError):

因为MyZeroDivisionError继承了ZeroDivisionError类，所以当mode为Ture时，调用do_the_division(mine)方法后，抛出了下面异常：

 raise MyZeroDivisionError("some worse news")

这个异常是能被except所捕获的：

except ZeroDivisionError:
        print('Division by zero')