diff --git a/grapple/settings.py b/grapple/settings.py
index 3b723042..c543eca5 100644
--- a/grapple/settings.py
+++ b/grapple/settings.py
@@ -72,7 +72,7 @@ def user_settings(self):
 
     def __getattr__(self, attr):
         if attr not in self.defaults:
-            raise AttributeError("Invalid Grapple setting: '%s'" % attr)
+            raise AttributeError(f"Invalid Grapple setting: '{attr}'")
 
         try:
             # Check if present in user settings
diff --git a/tests/test_image_types.py b/tests/test_image_types.py
index 5f6fbc7e..a80615ea 100644
--- a/tests/test_image_types.py
+++ b/tests/test_image_types.py
@@ -90,18 +90,15 @@ def test_renditions(self):
     def test_renditions_with_allowed_image_filters_restrictions(self):
         def get_query(**kwargs):
             params = ",".join([f"{key}: {value}" for key, value in kwargs.items()])
-            return (
-                """
-            query ($id: ID!) {
-                image(id: $id) {
-                    rendition(%s) {
-                        url
-                    }
-                }
-            }
-            """
-                % params
-            )
+            return f"""
+                    query ($id: ID!) {{
+                        image(id: $id) {{
+                            rendition({params}) {{
+                                url
+                            }}
+                        }}
+                    }}
+                    """
 
         results = self.client.execute(
             get_query(width=100), variables={"id": self.example_image.id}