Fixed missing or unused imports

src/pretix/base/services/cart.py

@@ -5,7 +5,7 @@ from django.conf import settings
 from django.db.models import Q
 from django.utils.timezone import now
 from django.utils.translation import ugettext as _
-from typing import List, Optional, Tuple
+from typing import List, Optional
 
 from pretix.base.i18n import LazyLocaleException
 from pretix.base.models import (

src/pretix/base/services/invoices.py

@@ -9,7 +9,6 @@ from django.conf import settings
 from django.contrib.staticfiles import finders
 from django.core.files.base import ContentFile
 from django.db import transaction
-from django.utils import translation
 from django.utils.formats import date_format
 from django.utils.translation import pgettext, ugettext as _
 from reportlab.lib import pagesizes

src/pretix/base/services/orders.py

@@ -16,7 +16,7 @@ from pretix.base.models import (
 from pretix.base.models.orders import InvoiceAddress
 from pretix.base.payment import BasePaymentProvider
 from pretix.base.services.invoices import (
-    generate_cancellation, generate_invoice, invoice_pdf,
+    generate_cancellation, generate_invoice,
 )
 from pretix.base.services.mail import mail
 from pretix.base.signals import (