# callback based

class BatchProcess(Item):

    def processIt(self):
        chain = RunChain(store=self.store, initialStep=self)
        chain.addStep(BatchStep1(store=self.store))
        chain.addStep(BatchStep2(store=self.store))



# state based

class BatchProcess(Item):
    step = integer(step=0)

    def drive(self):
        self.step += 1
        getattr(self, "step_%d")()

    def step_1(self):
        ...

    def step_2(self):
        ...