It is unlawful for any person liable to tax hereunder to fail or refuse to make application or return for a license or to pay the fee or tax or installment thereof when due, or for any person to make any false or fraudulent application or return or any false statement or representation in or in connection with, any such application or return, or to aid or abet another in any attempt to evade payment of the fee or tax, or any part thereof, or for any person to fail to appear, to testify falsely upon any investigation of the correctness of a return, or upon the hearing of any appeal, or in any manner to hinder or delay the city or any of its officers in carrying out the provisions of this chapter. (Ord. 129 § 20, 1970).