Where a function is assigned to a local authority under this Act F1or F3section 25 (provision of care and support services for persons who have or have had a mental disorder), 26 (provision of services designed to promote well-being and social development of such persons) or 27 (assistance with travel in connection with such services) of the Mental Health (Care and Treatment) (Scotland) Act 2003 (asp 13)F2 or Part II of the Children (Scotland) Act 1995F4or any of Parts 5, 6, 9 to 11, 13 to 16, and 18 of the Children’s Hearings (Scotland) Act 2011 (asp 1)F5 or Part 2, 3, 4, 5 or 6 of the Carers (Scotland) Act 2016, and a voluntary organisation or other person, including another local authority, is able to assist in the performance of that function, the local authority may make arrangements with such an organisation or other person for the provision of such assistance as aforesaid.