diff --git a/src/pretix/base/management/commands/shell_scoped.py b/src/pretix/base/management/commands/shell_scoped.py
index a593e3659..5638ee901 100644
--- a/src/pretix/base/management/commands/shell_scoped.py
+++ b/src/pretix/base/management/commands/shell_scoped.py
@@ -18,6 +18,7 @@ class Command(BaseCommand):
             cmd = 'shell_plus'
         except ImportError:
             cmd = 'shell'
+            del options['skip_checks']
 
         parser = self.create_parser(sys.argv[0], sys.argv[1])
         flags = parser.parse_known_args(sys.argv[2:])[1]
diff --git a/src/setup.cfg b/src/setup.cfg
index bc3753c56..370e5d13e 100644
--- a/src/setup.cfg
+++ b/src/setup.cfg
@@ -6,13 +6,11 @@ max-complexity = 11
 
 [isort]
 combine_as_imports = true
-default_section = THIRDPARTY
 include_trailing_comma = true
 known_first_party = pretix
 known_third_party = versions
-known_standard_library = typing,enum,mimetypes
+extra_standard_library = typing,enum,mimetypes
 multi_line_output = 5
-not_skip = __init__.py
 skip = make_testdata.py,wsgi.py,bootstrap,celery_app.py,pretix/settings.py,tests/settings.py,pretix/testutils/settings.py
 
 [tool:pytest]
diff --git a/src/tests/base/test_orderimport.py b/src/tests/base/test_orderimport.py
index 3a8facd75..3b9f21fb1 100644
--- a/src/tests/base/test_orderimport.py
+++ b/src/tests/base/test_orderimport.py
@@ -1,5 +1,5 @@
 import csv
-from _decimal import Decimal
+from decimal import Decimal
 from io import StringIO
 
 import pytest