自定义抛异常

class PricePolicyInvalid(Exception):
    def __init__(self, msg):
        self.msg = msg

from app01.utils.exception import PricePolicyInvalid
class Test():
    try:
        if True:
             raise PricePolicyInvalid("不合法")  # 主动抛异常

    except PricePolicyInvalid as e:  # 捕获异常
        ret = e.msg
    return ret