Is the testimony of a wet nurse regarding her own act of breastfeeding admissible?

Primary text

The testimony of a wet nurse concerning her own act of breastfeeding is accepted. This is established by the narration of Uqbah, where a Black slave woman stated, "I have breastfed you both," and the Prophet, peace be upon him, accepted her testimony. Furthermore, the act of breastfeeding does not result in a specific intended benefit for her, nor does it ward off harm from her, thus her testimony regarding it is accepted, similar to the testimony regarding other actions she performs.