Section 20
SEC. 20. Officers not to engage in certain transactions.&mdashIt shall be unlawful for any city officer, individually or as a member of a firm, to engage in any business transaction with the city, or with any of its authorized officials, boards, agents or attorneys, whereby money is to be paid, 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, or which shall be sold for taxes or assessments, or by virtue of legal process at the suit of the city; or to be surety for any person having a contract or doing business with the city, for the performance of which surety may be required; or to be surety on the official bond of any officer of the city; and shall not be financially interested in any transaction or contract in which the National Government or any subdivision or instrumentality thereof is an interested party.