from django.db.models import Sum

register = template.Library()

_ProductAndQuantity = namedtuple("ProductAndQuantity", ["product", "quantity"])

class ProductAndQuantity(_ProductAndQuantity):

    ''' Class that holds a product and a quantity.

    Attributes:

        product (models.inventory.Product)

class RegistrationCartTestCase(SetTimeMixin, TestCase):

    def setUp(self):

        super(RegistrationCartTestCase, self).setUp()

    def tearDown(self):

            # If you're seeing segfaults in tests, enable this.

                reset_sequences=False,

                allow_cascade=False,

        super(RegistrationCartTestCase, self).tearDown()

    @classmethod

    def setUpTestData(cls):

        cls.USER_2 = User.objects.create_user(

            username='testuser2',

            email='test2@example.com',

            password='top_secret')

        attendee1 = people.Attendee.get_instance(cls.USER_1)

            attendee=attendee1,

        )

        attendee2 = people.Attendee.get_instance(cls.USER_2)

            attendee=attendee2,

        )

        cls.RESERVATION = datetime.timedelta(hours=1)

        cls.categories = []

from django.contrib.auth.decorators import login_required

from django.contrib.auth.decorators import user_passes_test

from django.contrib import messages

from django.core.exceptions import ObjectDoesNotExist

from django.core.exceptions import ValidationError

from django.http import Http404

from django.shortcuts import redirect

from django.shortcuts import render

_GuidedRegistrationSection = namedtuple(

    "GuidedRegistrationSection",

    '''

    invoices = commerce.Invoice.objects.filter(

        user__attendee__access_code=access_code,

    ).order_by("-issue_time")

    if not invoices:

        raise Http404()

    unpaid = invoices.filter(status=commerce.Invoice.STATUS_UNPAID)

    paid = invoices.filter(status=commerce.Invoice.STATUS_PAID)

def _staff_only(user):

    ''' Returns true if the user is staff. '''

    return user.is_staff

@user_passes_test(_staff_only)

def manual_payment(request, invoice_id):

    ''' Allows staff to make manual payments or refunds on an invoice.

    This form requires a login, and the logged in user needs to be staff.

[flake8]