diff --git a/pypdf/_doc_common.py b/pypdf/_doc_common.py
index e8b7a0665..6757a6211 100644
--- a/pypdf/_doc_common.py
+++ b/pypdf/_doc_common.py
@@ -715,7 +715,7 @@ def indexed_key(k: str, fields: Dict[Any, Any]) -> str:
                 return (
                     k
                     + "."
-                    + str(sum([1 for kk in fields if kk.startswith(k + ".")]) + 2)
+                    + str(sum(1 for kk in fields if kk.startswith(k + ".")) + 2)
                 )
 
         # Retrieve document form fields
diff --git a/pypdf/_reader.py b/pypdf/_reader.py
index b04ea1761..16c24db09 100644
--- a/pypdf/_reader.py
+++ b/pypdf/_reader.py
@@ -1181,7 +1181,7 @@ def add_form_topname(self, name: str) -> Optional[DictionaryObject]:
         interim[NameObject("/Kids")] = acroform[NameObject("/Fields")]
         self.cache_indirect_object(
             0,
-            max([i for (g, i) in self.resolved_objects if g == 0]) + 1,
+            max(i for (g, i) in self.resolved_objects if g == 0) + 1,
             interim,
         )
         arr = ArrayObject()