add type validation

models/wait.py

@@ -57,7 +57,9 @@ class service_wait(osv.osv):
         self.write(cr, uid, ids, write_vals, context)
 
     def validate_service_wait_on_resolved_orders(self, cr, uid, order_state, reason_id, context):
-        reason = self.pool.get('service.wait.reason').read(cr, uid, reason_id)[0]
+        reason = self.pool.get('service.wait.reason').read(cr, uid, reason_id)
+        if type(reason) is list:                                                                                                        
+            reason = reason[0]
         if reason.get('customer_wait') and order_state == 'resolved':
             raise osv.except_osv(
                 _('ERROR!'),