Worklist.py: when getting matched state value, check if the state is existe to avoid error.

product/ERP5Workflow/Document/Worklist.py

@@ -137,7 +137,7 @@ class Worklist(IdAsReferenceMixin("worklist_", "prefix"), XMLObject):
           elif id == 'simulation_state':
             matches_id_list = self.getMatchedSimulationStateList()
           for state_id in matches_id_list:
-            if hasattr(self.getParent(), state_id):
+            if hasattr(self.getParent(), state_id, None):
               matches_ref_list.append(self.getParent()._getOb(state_id).getReference())
           matches = tuple(matches_ref_list)
         if id == 'causality_state':