diff --git a/quad/quads-typed.rkt b/quad/quads-typed.rkt
index 06c6ab8f..eba8c0a7 100644
--- a/quad/quads-typed.rkt
+++ b/quad/quads-typed.rkt
@@ -19,6 +19,8 @@
 (define-type QuadAttrValue Any)
 (define-predicate QuadAttrValue? QuadAttrValue)
 (define-type QuadAttrs (HashTable QuadAttrKey QuadAttrValue))
+(define-type HashableList  (All (A) (Rec duo (U Null (List* QuadAttrKey A duo)))))
+
 
 (: quad-attrs? (Any . -> . Boolean))
 (define (quad-attrs? x)
diff --git a/quad/utils-typed.rkt b/quad/utils-typed.rkt
index 59e8e802..fc6d3490 100644
--- a/quad/utils-typed.rkt
+++ b/quad/utils-typed.rkt
@@ -16,9 +16,8 @@
 
 ;; push together multiple attr sources into one list of pairs.
 ;; mostly a helper function for the two attr functions below.
-(: join-attrs ((Listof (U Quad QuadAttrs)) . -> . QuadAttrs))
+(: join-attrs ((Listof (U Quad QuadAttrs HashableList)) . -> . QuadAttrs))
 (define (join-attrs quads-or-attrs-or-lists)
-;  (list-of-mergeable-attrs? . -> . pairs?)
   (append-map hash->list (filter-not false? (map (λ(x)
                                                    (cond
                                                      [(quad? x) (quad-attrs x)]