§ 237. Penalties. Any person or persons, firm, partnership, corporation or association or any officer, director, employee or agent thereof who makes, or sells, or offers to sell or dispose of, or has in his or its possession, with intent to sell or dispose of, any article as herein defined to which is applied any quality mark which does not conform to all the provisions of this article, or from which is omitted any mark required by the provisions of this article, shall be guilty of a misdemeanor and upon conviction thereof shall be punished by a fine of not more than one thousand dollars or by imprisonment for not more than six months, or by both such fine and imprisonment in the discretion of the court provided however, that it shall be a defense to any prosecution under this article for the defendant to prove that the said article was manufactured and marked with the intention of and for purposes of exportation from the United States and that the said article was either actually exported from the United States to a foreign country within six months after date of manufacture thereof with the bona fide intention of being sold in the said country and of not being re-imported, or that it was delivered within six months after date of manufacture thereof to a person, firm or corporation whose exclusive customary business is the exportation of such articles from the United States.