According to Chapter 1, why is Goddess Saraswati invoked, and how is she related to Sai Baba and the writing of the Satcharitra?

The author of the Sai Satcharitra invokes Goddess Saraswati in Chapter 1, acknowledging that without the grace of the Goddess of Speech, no literary work can be accomplished. She is described as the daughter of Brahma, the Mother of the Universe and the Vedas, who holds the Brahma-veena and rides a swan. The author pleads for her to make him an instrument to share the nectar of Sai's life story with everyone. Chapter 1 then presents a profound non-dual concept by stating that Sai himself is Goddess Saraswati. In this form, Sai holds the Omkara-veena and sings his own life story for the salvation of his devotees, effectively becoming both the subject and the divine narrator of the sacred text.