diff --git a/bookwyrm/models/book.py b/bookwyrm/models/book.py
index 2e6377575..4ff377dbb 100644
--- a/bookwyrm/models/book.py
+++ b/bookwyrm/models/book.py
@@ -551,8 +551,12 @@ class Edition(Book):
 
         # clear author cache
         if self.id:
-            for author_id in self.authors.values_list("id", flat=True):
-                cache.delete(f"author-books-{author_id}")
+            cache.delete_many(
+                [
+                    f"author-books-{author_id}"
+                    for author_id in self.authors.values_list("id", flat=True)
+                ]
+            )
 
     @transaction.atomic
     def repair(self):
diff --git a/bookwyrm/utils/db.py b/bookwyrm/utils/db.py
index fd2601deb..7024d9e47 100644
--- a/bookwyrm/utils/db.py
+++ b/bookwyrm/utils/db.py
@@ -1,7 +1,7 @@
 """ Database utilities """
 
 from typing import Optional, Iterable, Set, cast
-import sqlparse  # type: ignore
+import sqlparse  # type: ignore[import-untyped]
 
 
 def format_trigger(sql: str) -> str:
diff --git a/bookwyrm/utils/partial_date.py b/bookwyrm/utils/partial_date.py
index 4c9391476..d5b3cabc3 100644
--- a/bookwyrm/utils/partial_date.py
+++ b/bookwyrm/utils/partial_date.py
@@ -222,17 +222,17 @@ class PartialDateDescriptor:
         return [("DAY", "Day prec."), ("MONTH", "Month prec."), ("YEAR", "Year prec.")]
 
 
-class PartialDateModel(models.DateTimeField):  # type: ignore
+class PartialDateModel(models.DateTimeField):  # type: ignore[type-arg]
     """a date field for Django models, using PartialDate as values"""
 
     descriptor_class = PartialDateDescriptor
 
-    def formfield(self, **kwargs):  # type: ignore
+    def formfield(self, **kwargs):  # type: ignore[no-untyped-def]
         kwargs.setdefault("form_class", PartialDateFormField)
         return super().formfield(**kwargs)
 
     # pylint: disable-next=arguments-renamed
-    def contribute_to_class(self, model, our_name_in_model, **kwargs):  # type: ignore
+    def contribute_to_class(self, model, our_name_in_model, **kwargs):  # type: ignore[no-untyped-def]
         # Define precision field.
         descriptor = self.descriptor_class(self)
         precision: models.Field[Optional[str], Optional[str]] = models.CharField(