• 枚举类不支持实例化；
• 成员的值不能在类的外部做任何修改，每个成员都有name,value两个属性，其中name为该枚举值的名称，value为该枚举值的内容；
• 定义枚举时，成员名称不允许重复，但在默认情况下，不同的成员值允许相同，两个相同值的成员，第二个成员的名称将会被视作第一个成员的别名，若要限制不能定义相同值的成员。可以使用装饰器@unique；
• 枚举支持迭代器，可以遍历枚举成员；如果枚举有值重复的成员，循环遍历枚举时只获取值重复成员的第一个成员，若想把值重复的成员也遍历出来，要用枚举的一个特殊属性:__members__；

from enum import Enum
from typing import Optional

class BaseEnm(Enum):

    def getCode(self):
        """根据枚举名称取状态码code

        @return: 状态码code
       """
        return self.value[0]

    def getMessage(self):
        """根据枚举名称取状态说明message

        @return: 状态说明message
        """
        return self.value[1]

    @classmethod
    def messageByCode(cls, code) -> Optional[str]:
        """根据状态码获取状态码说明"""
        for name, member in cls.__members__.items():
            if code in member.value:
                return cls[name].getMessage()
        return None

@unique
class CallStateResult(BaseEnm):
    """通话状态结果"""

    USER_STATE_NULL = (0, "未知的初始状态")
    USER_STATE_ANSWERED = (1, "接通")
    USER_STATE_POWER_OFF = (2, "关机")
    USER_STATE_NOT_EXIST = (3, "空号")
    USER_STATE_INVALID_NUM = (4, "非法号码")
    USER_STATE_OUTSERVICE = (5, "停机")
    USER_STATE_NOT_IN_SERVICE = (6, "不在服务区")
    USER_STATE_NOT_ANSWER = (7, "无人接听")
    USER_STATE_BUSY = (8, "用户忙")
    USER_STATE_NOT_REACHABLE = (9, "无法接通")
    USER_STATE_NOT_LOCALNUM_NEED_ZERO = (10, "本地号码未加零")
    USER_STATE_LOCALNUM_ADD_ZERO = (11, "本地号码多加零")
    USER_STATE_BARRING_INCOMING = (12, "呼入限制")
    USER_STATE_CALL_REMINDER = (13, "来电提醒")
    USER_STATE_DEFAULTING = (14, "欠费")
    USER_STATE_LINE_BUSY = (15, "网络忙")
    USER_STATE_FORWARDED = (16, "呼叫转移失败")
    USER_STATE_CANNOT_CONNECTED = (17, "无法接听")
    USER_STATE_NUMBER_CHANGE = (18, "改号")
    USER_STATE_LINE_FAULT = (19, "线路故障")
    USER_STATE_CALL_REJECTED = (20, "拒接")
    USER_STATE_NOT_RECOGNITION = (21, "未知状态")
    USER_STATE_CALL_FAILED = (22, "呼叫失败")
    USER_STATE_HANGUP = (100, "通话结束")


if __name__ == '__main__':
    print(CallStateResult.USER_STATE_NULL)
    print(CallStateResult.USER_STATE_NULL.getCode())
    print(CallStateResult.USER_STATE_NULL.getMessage())
    print(CallStateResult.messageByCode(0))

输出

CallStateResult.USER_STATE_NULL
0
未知的初始状态
未知的初始状态