diff --git a/cmd/tools/check_os_api_parity.v b/cmd/tools/check_os_api_parity.v
index fc2853bc9c..93c1051814 100644
--- a/cmd/tools/check_os_api_parity.v
+++ b/cmd/tools/check_os_api_parity.v
@@ -100,7 +100,7 @@ fn (app App) gen_api_for_module_in_os(mod_name, os_name string) string {
 			if s is ast.FnDecl {
 				fnd := s as ast.FnDecl
 				if fnd.is_pub {
-					fn_signature := fnd.str(b.table)
+					fn_signature := fnd.stringify(b.table)
 					fn_mod := fnd.modname()
 					if fn_mod == mod_name {
 						fline := '${fn_mod}: $fn_signature'