--- node_service.module (saved version)
+++ node_service.module (current document)
@@ -77,7 +77,7 @@
       '#args'             => array(
         array(
           '#name'           => 'node',
-          '#type'           => 'struct',
+          '#type'           => 'array',
           '#description'    => t('A node object. Upon creation, node object must include "type". Upon update, node object must include "nid" and "changed".'))),
       '#return'           => 'struct',
       '#help'             => t('Save a node object into the database.')),