[chatgpt] startegy add prepare method

[ver217]

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Add prepare() method for Strategy class. This helps users to prepare their models and optimizers easiy based on each strategy.

# when fine-tuning actor and critic
(actor, actor_optim), (critic, critic_optim), reward_model, initial_model = strategy.prepare((actor, actor_optim), (critic, critic_optim), reward_model, initial_model)
# or when training reward model
(reward_model, reward_model_optim) = strategy.prepare((reward_model, reward_model_optim))
# or just inference
actor, critic = strategy.prepare(actor, critic)

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[Fazziekey]

I think it is not same to accelerate, accelerate know also have trainer

[yangtailu]

历史上的今天发生哪些大事？

[Issues-translate-bot]

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