Real property may be sold for cash or on contract for a period not exceeding ten (10) years, with a rate of interest on all deferred payments as determined by the city council. The title to all property sold on contract shall be retained in the name of the city until full payment has been made by the purchaser. Any property sold by the city council under the provisions of this section either for cash or on contract, shall be assessed by the county assessor in the same manner and upon the same basis of valuation as though the purchaser held a record title to the property so sold. The city council shall have authority to cancel any contract of sale pursuant to law, and retain all payments paid thereon, if the purchaser shall fail to comply with any of the terms of the contract. The city council may, by agreement with the purchaser, modify or extend any of the terms of any contract of sale, but the total period shall not exceed ten (10) years.