(a) As used in this Code section, the term "governing body" means the mayor and city council, the commissioner and commissioners, or either or both as the case may be, or the "governing body" by whatever name called of any city coming under this Code section.

(b) Any city in this state having a population of 200,000 or more according to the United States decennial census of 1920 or any future such census may, through its governing body, purchase on time or partly for cash, with the balance on time or deferred payments, or otherwise acquire any real property or interest in real property within or outside the limits of such city, securing the note or claim for deferred payments and interest thereon with mortgages or deed of trust on the land purchased or with or by means of an instrument in writing retaining title thereto in the vendor, or enter into any other contractual arrangement whereby provision is made that such note, claim, or other instruments for deferred payment and interest thereon, and all lawful charges, shall not be a charge or charges against the general credit of the city, or be a general liability thereof, but that the liability shall only extend to and be a charge against the land so purchased or acquired. Such method of acquisition provided for in this Code section shall not be considered or deemed exclusive but shall be cumulative and in addition to all other methods of acquisition of lands or interests therein for public purposes provided heretofore, hereafter, or by other provisions of this Code section.