@abstract
    def clear_history(self):
        pass
Helper function to pick a desired volume state for given input
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/grizzled/grizzled/history.py/History.clear_history--crossover with--dataset/ETHPy150Open ClusterHQ/flocker/flocker/node/agents/functional/test_ebs.py/VolumeStateTransitionTests._pick_end_state