diff --git a/bookwyrm/signatures.py b/bookwyrm/signatures.py
index ff634232d..fb0ad49c1 100644
--- a/bookwyrm/signatures.py
+++ b/bookwyrm/signatures.py
@@ -28,7 +28,7 @@ def make_signature(method, sender, destination, date, digest=None):
     signature_headers = [
         f"(request-target): {method} {inbox_parts.path}",
         f"host: {inbox_parts.netloc}",
-        f"date: {date}"
+        f"date: {date}",
     ]
     headers = "(request-target) host date"
     if digest is not None:
@@ -46,6 +46,7 @@ def make_signature(method, sender, destination, date, digest=None):
     }
     return ",".join(f'{k}="{v}"' for (k, v) in signature.items())
 
+
 def make_digest(data):
     """creates a message digest for signing"""
     return "SHA-256=" + b64encode(hashlib.sha256(data.encode("utf-8")).digest()).decode(
diff --git a/bookwyrm/tests/activitypub/test_base_activity.py b/bookwyrm/tests/activitypub/test_base_activity.py
index 6ae446ff7..56bc142bb 100644
--- a/bookwyrm/tests/activitypub/test_base_activity.py
+++ b/bookwyrm/tests/activitypub/test_base_activity.py
@@ -14,7 +14,7 @@ from bookwyrm.activitypub.base_activity import (
     ActivityObject,
     resolve_remote_id,
     set_related_field,
-    get_representative
+    get_representative,
 )
 from bookwyrm.activitypub import ActivitySerializerError
 from bookwyrm import models
diff --git a/bookwyrm/tests/test_signing.py b/bookwyrm/tests/test_signing.py
index 54675d9d5..ec50a3da0 100644
--- a/bookwyrm/tests/test_signing.py
+++ b/bookwyrm/tests/test_signing.py
@@ -85,7 +85,9 @@ class Signature(TestCase):
         now = date or http_date()
         data = json.dumps(get_follow_activity(sender, self.rat))
         digest = digest or make_digest(data)
-        signature = make_signature("post", signer or sender, self.rat.inbox, now, digest)
+        signature = make_signature(
+            "post", signer or sender, self.rat.inbox, now, digest
+        )
         with patch("bookwyrm.views.inbox.activity_task.delay"):
             with patch("bookwyrm.models.user.set_remote_server.delay"):
                 return self.send(signature, now, send_data or data, digest)