What is due if the stipulated condition (suckling) becomes impossible before any part of the period commences?

Primary text

If the impossibility of the condition occurs before any portion of the period has passed, the wife owes the fair wage for suckling a similar child. The basis for this is that the compensation stipulated was a specific item that perished before its possession (qabd); therefore, its value or equivalent must be rendered, similar to if the Khul' was for a measure of grain (qafiz) that perished before collection.