Who is the shaykh whose saying is frequently repeated in Ibn Adi's book "Al-Kamil fi al-Duafa'"?

What is stated in Ibn 'Adi's book Al-Kamil fi Du'afa' al-Rijal where he says: "The Shaykh said," refers to Ibn 'Adi himself. Sometimes his name is explicitly mentioned as: "The Shaykh Ibn 'Adi said."

It is possible that the phrase "The Shaykh said" is from the words of the narrator of the book, Abu al-Qasim Hamzah ibn Yusuf al-Sahmi al-Jurjani, who was a student of Ibn 'Adi. This is similar to what is found in Al-Muwatta' by Imam Malik, narrated by Yahya ibn Yahya al-Laythi from Malik, where he says: "Malik said."