商城扩展外卖和跑腿怎么确认范围？用订单类型与停用规则验收

"""Deterministic model only; no network, database or production integration."""
from dataclasses import dataclass

ALLOWED = {
    'retail': {'created': {'picking', 'cancelled'}, 'picking': {'ready', 'cancelled'},
               'ready': {'collected', 'cancelled'}, 'collected': {'delivered'}},
    'meal': {'created': {'preparing', 'cancelled'}, 'preparing': {'ready', 'cancelled'},
             'ready': {'collected', 'cancelled'}, 'collected': {'delivered'}},
    'courier': {'created': {'accepted', 'cancelled'}, 'accepted': {'collected', 'cancelled'},
                'collected': {'delivered'}},
}
@dataclass(frozen=True)
class Order:
    kind: str
    state: str = 'created'
    revision: int = 0

def create(kind, enabled):
    if kind not in ALLOWED:
        raise ValueError('unknown business kind')
    if not enabled.get(kind, False):
        raise ValueError('new orders disabled')
    return Order(kind)

def transition(order, expected_revision, next_state):
    if order.kind not in ALLOWED or expected_revision != order.revision:
        raise ValueError('kind or revision conflict')
    if next_state not in ALLOWED[order.kind].get(order.state, set()):
        raise ValueError('illegal transition')
    return Order(order.kind, next_state, order.revision + 1)

def rejected(fn):
    try:
        fn()
    except ValueError:
        return
    raise AssertionError('expected rejection')

if __name__ == '__main__':
    flags = dict(retail=True, meal=True, courier=True)
    meal = create('meal', flags)
    rejected(lambda: transition(meal, 0, 'picking'))
    meal = transition(meal, 0, 'preparing')
    rejected(lambda: transition(meal, 0, 'ready'))
    courier = transition(create('courier', flags), 0, 'accepted')
    flags['courier'] = False
    rejected(lambda: create('courier', flags))
    courier = transition(courier, 1, 'collected')
    rejected(lambda: transition(courier, 2, 'cancelled'))
    courier = transition(courier, 2, 'delivered')
    assert courier.state == 'delivered'
    assert create('retail', flags).state == 'created'
    rejected(lambda: transition(courier, 3, 'accepted'))
    print('type isolation, revision conflict, stop-new, existing delivery: passed')