diff --git a/bookwyrm/views/feed.py b/bookwyrm/views/feed.py
index 49b8f73b8..165e662fc 100644
--- a/bookwyrm/views/feed.py
+++ b/bookwyrm/views/feed.py
@@ -11,7 +11,6 @@ from django.views import View
 
 from bookwyrm import activitystreams, forms, models
 from bookwyrm.activitypub import ActivitypubResponse
-from bookwyrm.models import User
 from bookwyrm.settings import PAGE_LENGTH, STREAMS
 from bookwyrm.suggested_users import suggested_users
 from .helpers import get_user_from_username
@@ -24,6 +23,7 @@ class Feed(View):
     """activity stream"""
 
     def post(self, request, tab):
+        """save feed settings form, with a silent validation fail"""
         settings_saved = False
         form = forms.FeedStatusTypes(request.POST, instance=request.user)
         if form.is_valid():
@@ -250,7 +250,11 @@ def get_suggested_books(user, max_books=5):
     return suggested_books
 
 
-def filter_stream_by_status_type(activities, allowed_types=[]):
+def filter_stream_by_status_type(activities, allowed_types=None):
+    if not allowed_types:
+        allowed_types = []
+
+    """filter out activities based on types"""
     if "review" not in allowed_types:
         activities = activities.filter(Q(review__isnull=True))
     if "comment" not in allowed_types: