diff --git a/std/tuples.ucg b/std/tuples.ucg
index e946610..ad2c786 100644
--- a/std/tuples.ucg
+++ b/std/tuples.ucg
@@ -58,7 +58,7 @@ let has_fields = module{
 
     let fs = lib.fields{tpl=mod.tpl}.result;
 
-    let result = reduce(reducer = func (acc, f) => acc && (f in fs), true, (mod.fields));
+    let result = reduce(func (acc, f) => acc && (f in fs), true, mod.fields);
 };
 
 // Check if a field in a tuple is a given type.
@@ -92,4 +92,4 @@ let field_type = module{
 
     // The computed answer true or false.
     let result = lib.has_fields{tpl=mod.tpl, fields=[mod.field]}.result && reduce(reducer, true, it);
-};
\ No newline at end of file
+};