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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def state_machines_set_notification(self, model, prop_name, info):
 """Observe all open state machines and their root states """

        if info['method_name'] == '__setitem__':
            state_machine_m = info.args[1]
            self.observe_model(state_machine_m)