http://habrahabr.ru/post/184156/

gistfile1.py

# -*- coding: utf-8 -*-
from random import randint


class Claim(object):
    STATE_START = 0
    STATE_ANALYZE = 1
    STATE_PROCESSING = 2
    STATE_CLARIFY = 3
    STATE_CLOSE = 4

    def __init__(self, state=STATE_START):
        self._state = state

    @property
    def state_handler(self):
        return {
            self.STATE_START: self.start,
            self.STATE_ANALYZE: self.analyze,
            self.STATE_PROCESSING: self.processing,
            self.STATE_CLARIFY: self.clarify,
            self.STATE_CLOSE: self.close,
        }[self._state]

    def run(self):
        while self._state is not None:
            self.state_handler()

    def start(self):
        print u'заявка подана'
        self._state = self.STATE_ANALYZE

    def analyze(self):
        print u'анализ заявки'
        if randint(0, 2) == 2:
            print u'заявка принята к исполнению'
            self._state = self.STATE_PROCESSING
        else:
            print u'требуется уточнение'
            self._state = self.STATE_CLARIFY

    def processing(self):
        print u'проведены работы по заявке'
        self._state = self.STATE_CLOSE

    def clarify(self):
        if randint(0, 4) == 4:
            print u'пользователь отказался от заявки'
            self._state = self.STATE_CLOSE
        else:
            print u'уточнение дано'
            self._state = self.STATE_ANALYZE

    def close(self):
        print u'заявка закрыта'
        self._state = None