No primary election shall be held for the nomination of candidates for the office of mayor, and candidates shall be nominated as herein provided. A person may also become a candidate for the office of mayor by filing a verified pauper’s oath with the city clerk, or by filing a verified petition containing an endorsement of candidacy by the signatures and addresses of 2,000 persons, each of whom is a registered voter residing in the city, provided that no such signature may be obtained more than 12 months immediately preceding the deadline for filing said statements of candidacy.