diff --git a/src/barril/units/unit_database.py b/src/barril/units/unit_database.py
index 95def37..e8f146f 100644
--- a/src/barril/units/unit_database.py
+++ b/src/barril/units/unit_database.py
@@ -1189,7 +1189,8 @@ def Convert(
                 return value
 
             if (
-                category_or_quantity_type.__class__ in (list, tuple)
+                category_or_quantity_type.__class__
+                in (list, tuple)  # type:ignore[comparison-overlap]
                 and len(category_or_quantity_type) == 1
             ):
                 category_or_quantity_type = category_or_quantity_type[0]