halacha - Sephardic Chakhamim mentioning Modeh Ani

Do the Ben Ish Chai, or other Sephardic Chakhamim speak on the recitation of "Modeh Ani" upon rising in the morning? One so-called Rabbi of the West African Jews of the Galut says that "Modeh Ani" is not obligatory or required to say, because it was not stated in the Talmud or the Rambam and other Sephardic Chakhamim.