diff --git a/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py b/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py
index 36302d1229..5a3300c08b 100644
--- a/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py
+++ b/src/ifcopenshell-python/ifcopenshell/express/rule_compiler.py
@@ -739,7 +739,7 @@ class AttributeGetattrTransformer(ast.NodeTransformer):
                 func=ast.Name(id="express_getattr", ctx=ast.Load()),
                 args=[
                     new_value,
-                    ast.Str(s=node.attr),
+                    ast.Constant(value=node.attr),
                     ast.Name(id="INDETERMINATE", ctx=ast.Load()),
                 ],
                 keywords=[],