Section 20
SEC. 20. Officers not to engage in certain transactions.-It shall be unlawful for any city officer, directly or indirectly, individually or. as a member of a firm, to engage in any business transaction with the city, or with any its authorized officials, boards, agents, or attorneys, whereby money is to be paid, directly or indirectly, out of the resources of the city to such person or firm; or to purchase any real estate or other property belonging to the city which shall be sold for taxes or assessments, or by virtue of legal process at the suit of the city; or to be surety any person having a contract or doing business with the city, for the performance of which security may required; or to be surety on the official bond of any the city.