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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 restore(self, hidden_state):
 """ Restore any state from checkpoint - currently not implemented but possible to do so in the future """

        for callback in self.callbacks:
            callback.load_state_dict(self, hidden_state)

        if 'optimizer' in hidden_state:
            self.optimizer_initial_state = hidden_state['optimizer']