python - Django oscar 標準の配送方法を追加

Question

django oscarの配送アプリをオーバーライドして、標準の配送料を請求する方法を誰か説明してもらえますか? ドキュメントに記載されているレシピを使用して試してみましたが、利用可能な配送方法が表示されません。これは私がやったことです：

アプリ/配送/admin.py:

from oscar.apps.shipping.admin import *

アプリ/配送/config.py:

from django.apps import AppConfig


class ShippingConfig(AppConfig):
    name = 'apps.shipping'

アプリ/配送/methods.py:

from decimal import Decimal as D
from django.template.loader import render_to_string

from oscar.apps.shipping import methods
from oscar.core import prices


class Standard(methods.Base):
    code = 'standard'
    name = 'Standard shipping'

    charge_per_item = D('0.99')
    threshold = D('12.00')

    description = render_to_string(
        'shipping/standard.html', {
            'charge_per_item': charge_per_item,
            'threshold': threshold})

    def calculate(self, basket):
        # Free for orders over some threshold
        if basket.total_incl_tax > self.threshold:
            return prices.Price(
                currency=basket.currency,
                excl_tax=D('0.00'),
                incl_tax=D('0.00'))

        # Simple method - charge 0.99 per item
        total = basket.num_items * self.charge_per_item
        return prices.Price(
            currency=basket.currency,
            excl_tax=total,
            incl_tax=total)


class Express(methods.Base):
    code = 'express'
    name = 'Express shipping'

    charge_per_item = D('1.50')
    description = render_to_string(
        'shipping/express.html', {'charge_per_item': charge_per_item})

    def calculate(self, basket):
        total = basket.num_items * self.charge_per_item
        return prices.Price(
            currency=basket.currency,
            excl_tax=total,
            incl_tax=total)

アプリ/配送/models.py:

from oscar.apps.shipping.models import *

アプリ/配送/repository.py:

from oscar.apps.shipping import repository

from . import methods


# Override shipping repository in order to provide our own two
# custom methods
class Repository(repository.Repository):
    methods = (methods.Standard(), methods.Express())