What is the required waiting period for a female slave divorced revocably ('talāq raj'ī) by her slave-husband, if her master subsequently frees her?

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If a slave divorces his wife with a revocable divorce and her master subsequently frees her, she observes the waiting period of a free woman, regardless of whether the divorce is formally dissolved or if she remains under the marriage contract. This is because she attained freedom during the revocable waiting period.