[Reformat] flake8 compatible

aleksis/core/__init__.py

aleksis/core/apps.py

aleksis/core/checks.py

aleksis/core/forms.py

aleksis/core/mixins.py

aleksis/core/models.py

aleksis/core/preferences.py

aleksis/core/settings.py

aleksis/core/tasks.py

aleksis/core/urls.py

aleksis/core/util/apps.py

aleksis/core/util/core_helpers.py

aleksis/core/util/middlewares.py

aleksis/core/util/notifications.py

aleksis/core/util/predicates.py

aleksis/core/views.py