573.12. Any contract under which a municipality entrusts a person with the responsibility of performing work for the conversion of its public lighting network and of administering and maintaining the network during the period determined in the contract may also entrust that person with the responsibility of assuming the financing of the costs relating to the acquisition of the network by the municipality, and may provide for the reimbursement of the costs by means of the payment of instalments to that person by the municipality for such amount and in such number as are determined in the contract.