In cases where the property of the utility proposed to be sold and conveyed or leased lies within, and the franchises and public duties thereof relate to a single municipality, and in cases where such a utility is owned by a corporation, and its capital stock is proposed to be sold, the question whether the proposed sale and conveyance or lease is consistent with the interests of the public shall be determined by the governing body of such municipality, and also by the Public Service Commission, and if the governing body of such municipality and the commission shall each determine that the proposed sale and conveyance, or lease, is consistent with the interests of the public, their determination shall be shown by their approval of the proposed sale and conveyance or lease.