枚举

from enum import Enum # pip install enum34
class Build(Enum):
    debug = 200
    build = 400

1. string to enum
   a=Build[‘debug’]
   output: ‘400’

2. enum to string
   a.name
   output: ‘debug’

3. .int to enum
   b=Build(400)

4. enum to int
   b.value