异常捕获，rasie可以改成return

def test(level):
    if level<5:
        raise Exception("没熟没熟")


try:
    test(5)               
except Exception as e:
    print(e)             
else:
    print("熟了 请吃")    

def test(level):
    if level<5:
        return "没熟没熟"

str=test(5)
if str=="没熟没熟":
    print(str)
else:
    print("熟了 请吃")