This subchapter applies only to a home-rule municipality that owns an electric utility system, that by ordinance or charter elects to have the management and control of the utility system governed by a board of trustees, and that:
(1) has outstanding obligations payable in whole or in part from and secured by a lien on and pledge of the net revenue of the system; or
(2) issues obligations that:
(A) are payable in whole or in part from and secured by a lien on and pledge of the net revenue of the system; and
(B) are approved by the attorney general.