好比這樣

def outter():
    try:
        inner()
    except IOError:
        #do something
    finally:
        #do something

def inner():
    try:
        #do something
    except IOError:
        raise
    finally:
        #do something

if __name__ == '__main__':
    out()

文章后面有舉例，上層調(diào)用指的就是外層的代碼(外層的try catch)。raise會將錯誤信息拋出給外層，然后外層try catch捕捉到異常后處理。