Book of Psalms Translated into Ethiopian (Gez)

Book of Psalms in Ethiopian script, in the Gez language used by the Ethiopian priests.
Handwritten in black, red and some blue and brown ink, on 11 parchment booklets. Number of leaves is different in each booklet. A few sketches and two illustrations: snakes and an angel.
Bound in a dark wooden binding with thick threads, no spine.
[70] leaves, 10 cm. Fair-good condition. On some leaves ink is somewhat faded or slightly deleted. Dark stains to borders. Front cover broken into 3 parts sewn with thread, and almost totally detached.
It is not clear to us whether this is a copy or commentary, and whether this is a traditional Book of Psalms or one with additions from foreign religions.