diff --git a/paperqa/types.py b/paperqa/types.py
index 845a045f..071f8008 100644
--- a/paperqa/types.py
+++ b/paperqa/types.py
@@ -124,10 +124,10 @@ def ensure_doc(cls, values: Any) -> Any:
                 try:
                     doc = DocDetails(**copy_doc_data)
                     values["doc"] = doc
-                except ValidationError as exc:
+                except ValidationError as e:
                     raise ValidationError(
                         f"Failed to deserialize doc data from {doc_data}."
-                    ) from exc
+                    ) from e
 
         return values