Is a Khul' (divorce by compensation) valid if the compensation stipulated is the suckling of the child for two years?

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The Khul' upon the condition of the wife suckling her child for two years is valid. This validity extends to specifying any known period, whether short or long. This view is held by Al-Shafi'i because such a condition is valid for compensation in other contracts, making it more permissible in Khul'. If the duration is not specified, the divorce is still valid, and the period defaults to the remaining portion of two years, as established by Ahmad. The basis for this is the Quranic verses that set the suckling period, specifically stating: "The mothers shall suckle their offspring for two whole years" (Quran 2:233), and "Its weaning is in two years" (Quran 31:14). Furthermore, "And his gestation and weaning period is thirty months" (Quran 46:15) implies two years for weaning when gestation is six months. The Prophet, peace be upon him, stated, "No suckling after weaning," meaning after two years, thus the unspecified term in human contracts defaults to this established period. Specifying the description of suckling is not required; the genus suffices, similar to stipulating the genus of tailoring in a lease.