§ 493. Attorneys forbidden to defend criminal prosecutions carried on by their partners, or formerly by themselves. An attorney, who directly or indirectly advises in relation to, or aids or promotes the defense of any action or proceeding in any court, the prosecution of which is carried on, aided or promoted by a person as district attorney or other public prosecutor, with whom such attorney is directly or indirectly connected as a partner; or who, having himself prosecuted or in any manner aided or promoted any action of proceeding in any court, as district attorney or other public prosecutor, afterwards directly or indirectly advises in relation to, or takes any part in, the defense thereof, as attorney or otherwise; or who takes or receives any valuable consideration from or on behalf of any defendant in any such action, upon any understanding or agreement whatever, express or implied, having relation to the defense thereof, is guilty of a misdemeanor.