diff --git a/src/pretix/presale/forms/renderers.py b/src/pretix/presale/forms/renderers.py
index 6ad66b4ee8..a94ca72c75 100644
--- a/src/pretix/presale/forms/renderers.py
+++ b/src/pretix/presale/forms/renderers.py
@@ -59,7 +59,7 @@ def render_label(content, label_for=None, label_class=None, label_title='', labe
         # usually checkboxes have overall empty labels and special labels per checkbox
         # => remove for-attribute as well as "required"-text appended to label
         if 'for' in attrs:
-            del(attrs['for'])
+            del attrs['for']
     else:
         opt += '<i class="sr-only label-required">, {}</i>'.format(pgettext('form', 'required')) if not optional else ''
 
diff --git a/src/setup.py b/src/setup.py
index 3222056510..49ed0884d9 100644
--- a/src/setup.py
+++ b/src/setup.py
@@ -239,13 +239,13 @@ setup(
             'coverage',
             'coveralls',
             'django-debug-toolbar==3.5.*',
-            'flake8==4.0.*',
+            'flake8==5.0.*',
             'freezegun',
             'isort==5.10.*',
             'pep8-naming==0.12.*',
             'potypo',
-            'pycodestyle==2.8.*',
-            'pyflakes==2.4.*',
+            'pycodestyle==2.9.*',
+            'pyflakes==2.5.*',
             'pytest-cache',
             'pytest-cov',
             'pytest-django==4.*',