diff --git a/aleksis/apps/alsijil/model_extensions.py b/aleksis/apps/alsijil/model_extensions.py
index c26ca8edeba9f1e74f550fe0ba9644308e831f8c..3f0b0df19bc8ed0ceb02b52f209fa7b74b668d64 100644
--- a/aleksis/apps/alsijil/model_extensions.py
+++ b/aleksis/apps/alsijil/model_extensions.py
@@ -126,6 +126,7 @@ Person.add_permission(
     "register_absence_person", _("Can register an absence for a person")
 )
 
+
 @LessonPeriod.method
 def get_lesson_documentation(
     self, week: Optional[CalendarWeek] = None
diff --git a/aleksis/apps/alsijil/util/alsijil_helpers.py b/aleksis/apps/alsijil/util/alsijil_helpers.py
index 98b143d4313522fa81254b5e8b7536bb3515122c..51279dc62615a8d5432a3b654095d8d10c895eaa 100644
--- a/aleksis/apps/alsijil/util/alsijil_helpers.py
+++ b/aleksis/apps/alsijil/util/alsijil_helpers.py
@@ -1,8 +1,9 @@
 from typing import Optional
 
-from calendarweek import CalendarWeek
 from django.http import HttpRequest
 
+from calendarweek import CalendarWeek
+
 from aleksis.apps.chronos.models import LessonPeriod
 from aleksis.apps.chronos.util.chronos_helpers import get_el_by_pk
 
@@ -16,7 +17,9 @@ def get_lesson_period_by_pk(
     """Get LessonPeriod object either by given object_id or by time and current person."""
     wanted_week = CalendarWeek(year=year, week=week)
     if period_id:
-        lesson_period = LessonPeriod.objects.annotate_week(wanted_week).get(pk=period_id)
+        lesson_period = LessonPeriod.objects.annotate_week(wanted_week).get(
+            pk=period_id
+        )
     elif hasattr(request, "user") and hasattr(request.user, "person"):
         if request.user.person.lessons_as_teacher.exists():
             lesson_period = (
diff --git a/aleksis/apps/alsijil/util/predicates.py b/aleksis/apps/alsijil/util/predicates.py
index 3b747b695a3f6f0e290965c849c2544d9e38fd7a..9f2424bfd03106030f21439d1eb18d18ead6435a 100644
--- a/aleksis/apps/alsijil/util/predicates.py
+++ b/aleksis/apps/alsijil/util/predicates.py
@@ -17,7 +17,10 @@ def is_lesson_teacher(user: User, obj: LessonPeriod) -> bool:
     in the lesson or the substitution linked to the given LessonPeriod.
     """
     if hasattr(obj, "lesson"):
-        return user.person in obj.lesson.teachers.all() or user.person in obj.substitutions.teachers.all()
+        return (
+            user.person in obj.lesson.teachers.all()
+            or user.person in obj.substitutions.teachers.all()
+        )
     return True
 
 
diff --git a/aleksis/apps/alsijil/views.py b/aleksis/apps/alsijil/views.py
index 96be3b77eb52cc5bb4047b909a1b892954bf9155..6e09bc743bc5444394d2b8b8bff1f6096be45b0b 100644
--- a/aleksis/apps/alsijil/views.py
+++ b/aleksis/apps/alsijil/views.py
@@ -10,9 +10,8 @@ from django.utils.translation import ugettext as _
 
 from calendarweek import CalendarWeek
 from django_tables2 import RequestConfig, SingleTableView
-from rules.contrib.views import permission_required
 from reversion.views import RevisionMixin
-from rules.contrib.views import PermissionRequiredMixin
+from rules.contrib.views import PermissionRequiredMixin, permission_required
 
 from aleksis.apps.chronos.managers import TimetableType
 from aleksis.apps.chronos.models import LessonPeriod, LessonSubstitution
@@ -21,8 +20,7 @@ from aleksis.apps.chronos.util.date import week_weekday_to_date
 from aleksis.core.mixins import AdvancedCreateView, AdvancedDeleteView, AdvancedEditView
 from aleksis.core.models import Group, Person, SchoolTerm
 from aleksis.core.util import messages
-from aleksis.core.util.core_helpers import get_site_preferences
-from aleksis.core.util.core_helpers import objectgetter_optional
+from aleksis.core.util.core_helpers import get_site_preferences, objectgetter_optional
 
 from .forms import (
     ExcuseTypeForm,
@@ -34,8 +32,6 @@ from .forms import (
 )
 from .models import ExcuseType, ExtraMark, LessonDocumentation
 from .tables import ExcuseTypeTable, ExtraMarkTable
-from .models import ExcuseType, LessonDocumentation
-from .tables import ExcuseTypeTable
 from .util.alsijil_helpers import get_instance_by_pk, get_lesson_period_by_pk