func (opt *Option) ArgVar(val *string) error
有传言是说，阿里内部对现有的开源模式有分歧，觉得开源的成本投入不划算，或者认为开源影响了阿里云卖自己的API。
，这一点在搜狗输入法下载中也有详细论述
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lambda v: v == value,
While the acoustic deterrent costs £50m, the wider fish‑protection system - including larger inlet heads and a return pipe for fish - will bring the cost to £700m.