def isVariableDefined(self, varID):
        
        for i in range(self.varList.count()):
            item = self.varList.item(i)
            if varID == item.getVariable().id and not item.isQuickplotItem():
                return True
        return False
1. mapper event listen on class
dataset/ETHPy150Open VisTrails/VisTrails/contrib/cdat/cdat_window.py/QDefinedVariable.isVariableDefined--crossover with--dataset/ETHPy150Open zzzeek/sqlalchemy/test/orm/test_events.py/DeferredMapperEventsTest.test_deferred_map_event