Enable and fix lint

src/wagtail_personalisation/forms.py

@@ -8,15 +8,11 @@ from django.contrib.auth import get_user_model
 from django.contrib.auth.models import AnonymousUser
 from django.contrib.sessions.models import Session
 from django.contrib.staticfiles.templatetags.staticfiles import static
-from django.core.exceptions import ValidationError
 from django.test.client import RequestFactory
-from django.utils import timezone
 from django.utils.lru_cache import lru_cache
 from django.utils.translation import ugettext_lazy as _
 from wagtail.wagtailadmin.forms import WagtailAdminModelForm
 
-
-
 SessionStore = import_module(settings.SESSION_ENGINE).SessionStore
 
 
@@ -29,7 +25,6 @@ def user_from_data(user_id):
         return AnonymousUser()
 
 
-
 class SegmentAdminForm(WagtailAdminModelForm):
     def clean(self):
         cleaned_data = super(SegmentAdminForm, self).clean()
@@ -62,7 +57,6 @@ class SegmentAdminForm(WagtailAdminModelForm):
             if field not in excluded:
                 form.add_error(field, _('Cannot update a static segment'))
 
-
     def save(self, *args, **kwargs):
         is_new = not self.instance.id