diff --git a/networks.rkt b/networks.rkt
index bd7f335..92e7ff4 100644
--- a/networks.rkt
+++ b/networks.rkt
@@ -10,13 +10,13 @@
 ;;; This model can generalise Boolean networks, TBANs, multivalued
 ;;; networks, etc.
 
-(require "utils.rkt" graph)
+(require "utils.rkt" "generic.rkt" graph)
 
 (provide
  ;; Structures
  (struct-out dynamics)
  ;; Functions
- (contract-out [update (-> network? state? (listof variable?) state?)]
+ (contract-out [update (-> network? state? (set/c variable? #:kind 'dont-care) state?)]
                [make-state (-> (listof (cons/c symbol? any/c)) state?)]
                [make-network-from-functions (-> (listof (cons/c symbol? update-function/c)) network?)]
                [update-function-form->update-function (-> update-function-form? update-function/c)]